During the Super Bowl 2000 episode, "Slaw" says he has to go to a engagement with his Dad and can't watch the Super Bowl. Later in the episode, he's watching it with Nick and company.
If you look closely at Nick's face mask when he is Bart Starr, you'll see it's a two-bar face mask. When the camera goes to footage of the game, the real Bart Starr is wearing a one-bar face mask.