The wide 7-ply laminate concave skateboard that Tyson the bulldog rides at the championship was not available in 1977. Laminate decks existed but they were flat and narrow. Skateboards in 1977 rarely exceeded 7-8 inches wide. Tysons board is obviously a 10 inch wide mid to late '80s pool/ramp model with wider trucks and "new school" wheels.
When Stacey and Kathy leave after the first competition, they get in his car, and Stacey exclaims the Skip called him bro, and said, "You look hungry, bro." When really, Skip had said, "Hey, bro, you're lookin' hungry."
What are the differences between the Theatrical Version and the Unrated Version?
The Unrated Version of the movie offers additional plot scenes as well as scenes with words which seemed to be not suitable for a PG-13 rating. Altogether the Unrated Version runs approx. 200 seconds longer than the Theatrical Version. A detailed comparison between both versions with pictures can be found here.