Andy says to Barney "A few weeks ago you got a hold of Gypsy cards and lamps and you had Opie making wishes ..." this is a reference to the Season 5, episode 14 "Three Wishes for Opie"
This is one of the rare times that incidents from earlier episodes are mentioned (there are two). First, Andy mentions Opie getting wishes from a lamp from an episode that aired a month earlier. Second, Goober mentions Gomer being in the Marines which references the episode with Gomer joining the Marines.
The title of the girlie magazine Andy finds at The Dump is "Tales of Love."
Andy switches hats with Barney while Barney is asleep in the back room at the Courthouse.
Barney has another accidental misfire of his pistol at the gun range. The eleventh of the series.