When Johnny is sitting on the couch in Andy's office, he refers to "WKRP in Pit-," cuts himself off, then says "Cincinnati." One of the cities under consideration for the series was Pittsburgh, PA (which would have made it WKRP in Pittsburgh, PA). The then-current mayor decided against giving permission for the studio to use Pittsburgh for the series.
Les can be seen wearing a bandage on some part of his body in practically every show. We eventually find out it is because he has a very large (and never-seen) dog that he keeps at home. In real-life, the bandage idea originated when Richard Sanders suffered an injury prior to the taping of the pilot and was forced to wear a bandage on the air; he subsequently decided to make it Les' trademark.
This pilot was a reunion for Gordon Jump, Howard Hesseman, and director Jay Sandrich. Jump played Chief of Police Tinkler and Hesseman was prosecuting attorney Franklin in several late first season episodes of Soap (1977), all directed by Sandrich. Notably, this pilot was the only episode of WKRP directed by Sandrich.
Howard Hesseman, who played DJ Johnny Fever, enjoyed working on the show but--having had some experience working in radio early in his professional career--always noted the ways it was very fictionalized. In particular, real-life DJs loved the show and would compliment Hesseman for the varied playlists Johnny Fever was able to use; Hesseman would explain to them that WKRP wasn't a real radio station and that a real-life Johnny Fever would have to play the kind of music the station management ordered.
The KISS poster that Andy puts up in his office while talking to Johnny, is one of the band from 1976 when they did the photo as a promo tied into the United States' bicentennial celebration. It was also the first appearance of the band as their "KISS Army" persona.