As Ernest T. approaches the courthouse and Andy tracks his progress by phone calls, he hangs up and tells Barney to go out the front and he will go out the back. After Barney confronts Ernest T. in front of the jail, Andy emerges from the shared entryway of the barber shop and TV repair shop, which is on the opposite side of the courthouse's back door.
When Andy and Barney spot the men carrying the window pane down the street, Andy remarks that it's the replacement glass for the one Ernest busted, so the men are carrying the glass to the courthouse. However, the way the layout of the town has been established throughout the series, the men are actually walking away from the courthouse, not towards it.
The Army doctor uses an otoscope to look into Ernest T.'s ears, but he doesn't use it properly. He should be looking through the lens, not over it.
After Ernest T. Bass gets Barney's uniform, the sheriff's star patch is missing from the shoulder. EDIT: Andy removed all Sheriff's Dept insignia, especially the badge, before giving the uniform to Ernest T. Bass.
When the two workers carrying the glass encounter Bass, they obviously turn the glass to make a better target for him and for Barney to hit with his revolver.
When trying to warn the recruiting sergeant not to take Ernest T. Bass, Andy mentions the events of Ernest's first appearance in the season three episode, "Mountain Wedding" and about how he was harassing Charlene Darling. He tells the sergeant that Ernest kidnapped the bride, Charlene. However, in that episode, Andy fooled Ernest into thinking that he had kidnapped Charlene by having Barney disguise himself as the bride.
Members of the film crew are reflected in the pane of glass the workers are carrying to the courthouse.