Barbara Christopher, wife of William Christopher (Father Mulcahy) appears with him and they sing a duet to entertain the crowd while Klinger repairs the movie film. Her character's name is Lieutenant O'Connor. Barbara's real-life maiden name is O'Connor. This is her only credited appearance.
The photo of Mildred Potter on the corner of Colonel Potter's desk is of Harry Morgan's real-life wife, Eileen Ann Detchon, and Colonel Potter says he and Mildred have been married 27 years. At the time this episode aired, Harry Morgan and his wife Eileen had been married for 35 years, having married in 1940.
Richard Lee-Sung, Cho in this episode, was a graduate of Belmont HS in 1949 was followed by service in the US Marine Corps during the Korean War and earned the Purple Heart as a survivor of the battle of the Chosin Reservoir, one of the worst battles of the Korean War.
The horse given by Radar to Colonel Potter in this episode is a male. In all future episodes, it is a mare (female), who Potter names "Sophie."
At the beginning of the episode, when Radar is folding the piece of paper, you can clearly see Gary Burghoff's left hand. It is deformed due to a birth defect and usually hidden behind a clipboard, etc.