The band performing in the nightclub, where Gomer loses Janice, was The Factory, featuring guitarist Lowell George, and drummer Richie Hayward. They would go on to form the critically acclaimed '70s band, Little Feat.
In the Go-Go bar, the walls are covered with band posters. When Gomer and Sgt. Carter are near the phone booth, you can see a Grateful Dead poster and a Country Joe and the Fish poster on the wall.
In the closing credits, the 'go-go club music' is credited to: "The Factory: Lowell - Warren - Martin - Rich. Courtesy of Universal Records"