The "Cody Coyote" was actually a kit car replica of the McLaren M6GT called the Manta Mirage that was made by Manta Cars from the late 1970s to 1986. It would have been a 1982 or 1983 model if it was new.
Hardcastle's comic book collection includes The Lone Ranger #61 (July 1953), seen laying on his desk when Hardcastle and McCormick enter the office. Below that issue is The Lone Ranger #67 (January 1954), which McCormick holds up mockingly, but which issue he is later seen reading in Hardcastle's truck. McCormick later calls Hardcastle "Kemosabe" and uses the line, "Get 'em up, Scout!" which was Tonto's equivalent to the Lone Ranger's "Hi-Yo, Silver!"
Hardcastle tells Mark his wife died ten years earlier. He also says that his parents were sharecroppers in Kansas. Later in the series, he is from Arkansas.