It's unlikely that Jackie took the same exam as Eric since she is a freshman and Eric is a senior.
At the beginning, when Midge says that Bob loves to take a bath, you can see that he's wearing shorts in Kitty's dream sequence.
When Eric makes out with Kate in his bedroom, there is a model of a F-20 Tigershark fighter on the table. The time of this episode was 1976, but this aircraft wasn't unveiled to the public until 1982.
When everybody is hanging out at "The Hub", there are adhesive labels on the Coca-Cola bottles. During the '70s, they were printed onto the bottle using white ink.
Kitty mentions stopping by Piggly Wiggly the day that this show takes place, which is in 1976 Wisconsin, but Piggly Wiggly wasn't introduced in the Midwest until 1998.