It wasn't uncommon for Roy Huggins to borrow from one of his series for the sake of another one. And for Rockford he reused things from Garner's most famous series, Maverick. (The Rockford episode about the Blue Lake Development Co. was a complete remake of Maverick's "Shady Deal at Sunny Acres", which would be subsequently remade in Alias Smith and Jones.) Here they harken back to when Maverick would quote one of his Pappy's sayings, which were clever and fit in nicely with plot. Jimmy Joe's sayings are borderline nonsense, and were presumably designed to just annoy Lessing.
Larry Hagman who plays Richard Lessing / Paul T. Grisham is portraying an oil man in a prelude to the soon to be J. R. Ewing in 'Dallas'.
The "silverfish" that Angel puts into meals in restaurants are actually earwigs.
Familiar character actor William Boyett provides the telephone message voice heard at the beginning of the show.
Guest star Larry Hagman is reunited here with three others who also appeared in "I Dream of Jeannie" with him: Denny Miller, Ron Masak and Michael Margotta. Margotta is uncredited here (he's the "witness" brought in to say Jim was seen under the plane.)