Jack Gallo is playing a banjo in Finch's dream sequence. George Segal was an accomplished banjo player in real life.
While trying to fix-up Jack with his mother, Finch mentions making Jack look like a "sea captain". This is a double reference / in-joke:
First - the actress playing Finch's mother, Joyce Bulifant is probably best known for playing Marie Slaughter, wife of Murray Slaughter, on "Mary Tyler Moore".
Second- Gavin MacLeod (the actor who played Murray Slaughter) is probably best known for playing Captain Merrill Stubing on "The Love Boat" who was a "sea captain".