In the scene where she's at the bar talking to Isaac about finding Roxy Blue, Lauren Tewes is clearly not wearing a bra.
Jim Nabors (Robert Tanner) and Olan Soulé (Harvey Grove) each played on 'The Andy Griffith Show' (1960-1968). They played 'Gomer Pyle' and 'John Masters' respectively.
While Isaac (Ted Lange) and Roxy (Diahann Carroll) are chatting, Isaac makes the comment, 'Yeah, but you walked out on Bob Hope!' Roxy responds, in part, 'They'll just get Donnie and Marie (Osmond)'. Donnie Osmond appears later on another episode of Love Boat (s3, e18 & e19- Kinfolk / Sis & the Slicker / Moonlight & Moonshine / Too Close for Comfort / The Affair- Parts 1 and 2) as country bumpkin-turned-singing star Danny Fields (Danny Scofield).