All of Sam's piano playing is actually Scott Bakula playing.
Even though he doesn't remember how to play piano, Al tells Sam he played Carnegie Hall at age 19.
Unusually, Al does not make his first appearance until 14 minutes into the episode.
Takes Place 1 Day Before The Beatles arrive in America for The First Time
This is the first of two episodes in which Sam leaps into a professional pianist. He would later do so again in Piano Man - November 10, 1985 (1991).