When Sam Malone removed his hairpiece, Rhea Perlman was genuinely shocked. In the original script, Sam was supposed to tell Carla that he wears a hairpiece, not show her. Although Rhea was obviously aware of Ted Danson's hair situation, she and the cast/crew were none the wiser that he was going to improvise.
This was actually the last episode filmed. The 90-minute finale was taped in March to accommodate Shelley Long's schedule.
Above the jukebox, there is a caricature by Al Hirschfeld of Charles, Burrows, Charles--the creators of Cheers.
Tattoo parlors were outlawed in Massachusetts from 1962 until October of 2000. Cliff and Norm must have crossed state lines.