The particulars of that first camp, his very first skate at the 'Dome, have been swallowed up in the gathering mists of the passing years.
"I do remember being really nervous," an older, more mature, polished-to-a-professional-sheen Mark Giordano is recalling, "And a little bit scared.
"Iggy, obviously, was here. Reggie. Rhett Warrener. Daymond Langkow. Roman Hamrlik, I think. Kipper in net, of course.
"These are guys I'd watched on TV.
"It can be a bit intimidating.
"Those first practices are when you really get a feel for the speed of the game; how fast everything moves out there.
"Then, when you get here and do that, you realize that you can actually keep up."
He was 20 in the fall of 2004. For all intents and purposes unknown. An undrafted free agent. As raw as meat in a butcher's window.
He had hair.
"Back then," recalls Jim Playfair, coach/GM Darryl Sutter's trusted assistant coach and in charge of the defence during that era, "you were able to put on more than one five- or seven-day development camp. So Darryl thought we should put one on every six weeks from the end of the season.
"We arranged a defencemen-only camp, maybe an hour, hour and a half on the ice every day, and I had designed these drills.
"Gio was an overage player, had a broken thumb and wasn't able to train the way he'd have liked heading into that camp. But doing the drills, the quick-feet at the back of the net, moving pucks, passing pucks hard, taking two steps out of the hole … all the small details you look for in a young defenceman, he had in spades.
"Real quiet kid, so his personality didn't jump out. But his skill did.
"I remember telling Darryl: 'This guy's going to be a good player.'"
Others, at first glance, weren't so convinced.
"To me," confesses Warrener, "he was just a guy going hard. Well, lovely. Lots of guys go hard.
"Shows what I know.
"He did work his butt off. But, honestly, I thought he was gonna be a seventh defenceman, maybe work his way up to a 5-6."
And now look at him.
After signing on here, Young Gio spent a full season in Lowell as a Lock Monster, during the NHL lockout.
The next year, he'd make his NHL debut on Jan. 30, 2006 against the St. Louis Blues and wear the Flaming C on six further occasions, spending the majority of time with the AHL Omaha Ak-Sar-Ben Knights.
As it happened, Giordano's first semi-regular campaign at the top level, '06-'07, a 48-game audition, coincided with the arrival of a comet: The much-ballyhooed Dion Phaneuf, the ninth-overall pick in the 2003 draft.
In those formative years here, The Dion could hit indolent forwards with the force of an ornery mule kick and hammer the puck just as hard.
For his swashbuckling style, Phaneuf generated headlines, compiled 50 points and was selected as a Calder Trophy finalist.
"I know Mark and Dion were quite close," says Regehr. "But Dion was his opposite in every way. He was a very large personality. You heard him coming a mile away. And his playing style matched the personality, all of a sudden he'd make a big impact in a game with a hit or goal.
"Mark was the absolute flip-side. Just minded his own business, kept quiet, continued to work on his game and boom!, the last four or five years, at an age where a lot of players are in the twilight of their careers, their production and play are in decline, he's gone the opposite way."
The process of building an all-around game had commenced.
"When he first arrived, you could see the offensive abilities were there," recalls Iginla, the man who Giordano would years later succeed as team captain. "He was the type of guy you were like 'Whoa! I want to be on the ice with him.' Maybe they were more worried about his play away from the puck at the start but, for me, I thought his offensive instincts always stood out."
For left-winger Alex Tanguay, another key arrival in '06-07, a different intangible jumped out.
"What I remember about him as a young player is the compete level. Is he the smoothest skater? No. Does he have the smoothest hands, do the toe-drags? No.
"But he had this will, this understanding that he had to get better. Since the day he got the NHL he's never stopped growing as a player. And that's to his credit. Smart hockey players always find ways to do that.
"What sets him apart today, what's made him a leading Norris Trophy candidate, is not only his competitiveness but his understanding of the game, his positioning.
"He's taken his game to another level because not only does he play well offensively but the defensive game is second to none."
A controversial breakthrough was triggered when Giordano, dissatisfied with the prospect of potentially spending most of another season at the minor-league level, left for Dynamo Moscow and the Russian Super League in the fall of 2007.
"I was a bubble guy and I got a good offer over there," he says now. "Looking back, yeah, it was ballsy, to be honest.
"But I was prepared if I had to stay there. Other guys were using it as leverage. I was more along the lines of: 'If I have to make a career out of this, I can.'
"Always in the back of your mind, though, you're thinking about coming back."
Of that nomadic winter spent in the Super League, Playfair has famously said: "I don't think he went to Russia because he liked the weather there. I don't think he went to Russia because he wanted to learn Russian. He didn't go to make a bunch of money. He didn't go to stick it (to anybody).
"He went over to play."
More than a few eyebrows tilted in surprise, or shock, though.
"Sometimes," says the 2019 edition of Giordano. "You feel good about standing up for yourself.
"At the end of the day if you believe in something, or yourself, you've got to stand up. Especially in this game. There are a lot of ups and downs.
"If you don't have belief in your own capabilities, you have no chance.
"I did what I thought at the time was right. Maybe people didn't agree with it but at the end of the day it worked out.
"I do look back and I'm proud of my decision."
That year spent in the shadow of Red Square, the Kremlin and the DQ ice-cream spiralling dome of St. Basil's Church, Giordano played 50 games and, as he says, fast-tracked his development as a player.
"It was a different experience, for sure," he recalls. "The weirdest thing was a black bear on a leash in downtown Moscow on a sidewalk.
"Now that's something you don't see every day.
"Then our team went on a big losing streak, the coach was let go, a new guy came in, we continued to lose. We ended up going as a team, on the team bus, to a small town, to a Russian orthodox church, where we had our sticks blessed.
"The funniest part of the story is we won the next game."
By the following September, as everyone knows, he'd returned.
"I'm grateful to Darryl," says Giordano now, "because if he really wanted to he could've put the screws to me. But he wasn't about that. He was about getting the best players in the lineup.
"The biggest thing for me is that I was more confident coming off that situation. I came back in the room feeling better about myself and my game and the boys were accepting."
Playfair remembers bringing Giordano back to Calgary.
"Darryl called me into the office and said: 'I'm thinking of making this offer to Gio. What do you think?' And I told him: 'At this point in his career, to stand up to everybody, to everything, and have the nuts to go to the unknown of Russia because it's the second best league in the world to improve his game, you know what I think …'
"Darryl started laughing and said: 'Good point.'"
Young Gio had begun the transformation into the Gio of today.
A Gio in Year 6 of wearing the C with distinction, moving up the franchise ladder in all manner of career categories, certain to be perched right at the apex of Norris contenders at season's close.
"At no point initially did I envision him developing into the player you see today," confesses Regehr. "I don't think anybody could have.
"Not just on the ice but in leadership qualities.
"The last few years, he's been absolutely lights-out.
"But that's a big part of the charm of the story, isn't it?
"And it is a fantastic story."
Sometimes out of the most unlikely of beginnings …
"He's 35," says Warrener, "and blowing everyone's minds.
"What is he? Plus-36. I mean, that's crazy good.
"I think back. He wasn't a big guy. He wasn't Brent Burns. He wasn't Scott Niedermayer with that natural stride. He wasn't mean like Chris Pronger or Robyn Regehr.
"But maybe that's the testament. Maybe that's the sign.
"Not a lot of people believed him at the start, I'll bet. But he believed in himself.
"That belief never wavered.
"And maybe that's the lesson, right?'"