The helmets in the stock football footage have an insignia on the side. The helmets in the footage shot for the episode don't.
When Nancy & George are sitting in Nancy's Ford Mustang II and listening to the football game on the radio, a shot of the radio and part of the dashboard is shown. What is shown is not what would be found in a Ford Mustang II. What's shown is the dashboard and radio that would've been in a midsize GM built car of the mid 70's.