I don't even know if you can purposely practice that play in the Olympic gold medal game and have it work to perfection like that. Think about that play, Pronger breaks into the zone, puts on the brakes and slides a pass to Lemieux who is about to enter the slot. Lemieux fakes out everyone on the ice except for Kariya who wisely enough had the skill to see it coming (I wouldn't blame him if he didn't). Look at Richter on that play, he was always built for these big games but even he is just completely faked out and is terribly out of position, as any goalie would be. Mario got an assist on that because he passed it to Pronger initially but just think about it, he could have gone pointless on that play and yet he was the architect of it without touching it.
Anyway, a resounding YES, he helped his legacy. Even though Mario retired as a 50-goal 122 point man in 1997 there was still the odd criticism of him. Once he came back that went away. His play in 2001 was incredible, and even though the next season he was injured mostly he still was great in the Olympics. His 2003 season was still pretty good even though that was a terrible Penguins team and he was doing all the work. 91 points in 67 games, let's just pause for a moment and realize that neither McDavid or Crosby did that this year and Lemieux did this when he was 37. I remember early on in that season, the torrid pace he was on before he got hurt. He was literally making a mockery of the scoring race and there was criticism of the NHL, not him, because how could someone his age dominate like that? He missed about a month, otherwise he wins the scoring title. In the first three months of the year he had 64 points in 37 games. In the first two months, 46 in 22. Just unreal.
Lastly, he was good in the 2004 World Cup. It was the last we would ever see of Mario to be honest because he still had some moves. Watch that opening goal vs. Finland in the championship game, he just corrals that puck so seamlessly around the Finnish forward.