The car radio plays the original 1964 rendition of "Dancing in the Street" by Martha & The Vandellas 16 months prior to its Motown release.
At the shop in Abilene, an Allstate location is seen across the street, with the company's logo clearly displayed. That version of the Allstate logo was not in use until 1969.
When the police ask the store owner to describe Sam, he mentions that Sam's character hadn't shaved for a couple of days, but had a mustache. Of course, the store owner should have seen the man Sam leaped into, and earlier in the episode Buster's outward appearance was a man with a full grown mustache and beard.