The scene at Warner Bros. Studios, the home studio of this show, features in-joke references to the show's two producers, Howie Horwitz (a tour bus labeled "Howie's Charter Service") and William T. Orr, who is often credited on-screen as Wm. T. Orr (the studio head is named Wm. T. Hart).
It seems the only pairing in Maverick of Roger Moore as Beau Maverick and Merry Anders as Maggie was Season 4 Episode 3, "The Town That Never Was". In this 77 Sunset Strip episode the scene shown filming on Stage 3 of Warner Brothers was not actually in the Maverick episode. In fact, Merry Anders was paired with John Astin and did not kiss Roger Moore as depicted in the 77 Sunset Strip filming of the Maverick scene.