Those season records are a pet peeve of mine. When I was a kid they had just started playing 14 games, up from 12. Career records are the same.
Actually average yards per game doesn't mean much. In the olden days defenders could beat the crap out of receivers until the ball was in the air. I remember a close game where the Bears were on defense late in the game. The opposing QB threw a pass to an open receiver in the middle of the field, but he collapsed before the ball got to him. Everyone was confused until they showed the replay. Butkus has clotheslined him as he ran by. Announcer said something like, "That was perfectly legal, the ball was still in the quarterback's hand. That's one of the many reasons that you don't just run across the middle of the field."
It was illegal to hold onto a defender's jersey regardless of where your hands were. Inside the shoulder pads was still holding, and the penalty was 15 yards. OTOH defensive linemen were more run stoppers instead of pass rushers because it was 3 yards and a cloud of dust. Yeah, I said dust. There was dust unless it rained, then it was mud.
Penalty on kickoff, block in the back, holding, clipping, was 15 yards. Backed you up 15 yards and the offense started with first and 25. Same on a punt, penalty during the return was going to mean first and 25.
Username checks out.