(The actor who plays) Norm wasn't 34 in that picture, he was 39, because this picture isn't from 1983, it's from 1987. It's the picture in the sidebar for his Wikipedia article, which explicitly states that this picture is from season 5.

This is what Norm looked like at 34. If he wasn't morbidly obese, he'd probably look about as young as the guy on the right. Of course, both are guaranteed to be wearing makeup, so the entire comparison is meaningless.