Jack Nicholson would share a scene with Ron Howard's dad, Rance Howard, in the movie Chinatown (1974).
The first of 2 appearances by Jack Nicholson on "The Andy Griffith Show" before he became a superstar--the 2nd is Episode 7 from Season 8.
When Opie turns on the radio at the beginning of this episode, the song coming from the radio is the exact same song that the teenagers dance to in the previous episode, "The Senior Play."
This is Sheldon's first appearance as Arnold. He essentially replaced Johnny Paul Jason as Opie's best friend. He's the only kid actor to have a continuing on-screen role in Opie's life. Arnold was more cerebral and well-read than Opie, and his imagination, and tendency to prevaricate, would affect numerous plot points. On the other hand, Opie, like his father, was the moral compass of the two.