Beer by Boulevard Brewing Company is featured prominently several times in the movie which is set in 1988. Boulevard was first brewed in late 1989 and wouldn't have been widely available until 1990 (not available until even later in bottles).
When TJ is paying of Russ and his friends at the end of the movie, he is giving them $20 bills that would not have been in print in 1988. The new design for the twenty dollar bill wasn't in circulation until 1998. Series 1985 or older would have been in circulation in 1988.
Lenexa's police cars have never had all blue light bars on them. In 1988 the police cars had red light bars. Lenexa's police cars have always been black and white, not blue.
Andy Lausier works for Bradshaw County Parks and Rec. Lenexa is located in Johnson County, KS. There is no Bradshaw County in Kansas or Missouri.