A Black Day for Mayberry - S4-E7
Continuity mistake: At the beginning of the show, two men walk into the courthouse. (As a sidenote, one of the men is Rance Howard, which is Ronnie Howard's real dad). Barney is the only one there, as Andy is out. The two men sit down to wait for Andy. Rance Howard is not wearing a hat, and he is in a light-colored suit. When Opie walks through the door looking for Andy, you can see that Rance is not sitting there any more, and now it's a man with a dark suit and wearing a hat. (00:01:55)
A Black Day for Mayberry - S4-E7
Plot hole: There is no reason for a gold truck from Denver to Fort Knox to be going through Mayberry.
A Black Day for Mayberry - S4-E7
Plot hole: About 2/3 through the show Barney is locked inside the armored car and Gomer puts about a gallon of gas into the gun port onto Barney's shoes. After Gomer is told of his error, Barney stays inside the truck. The fumes would have killed him, not to mention the risk of explosion.
A Black Day for Mayberry - S4-E7
Character mistake: When Opie comes in at the beginning of the episode and asks where Andy is, the exchange ends with Barney asking "Something you want to see him about?" and Opie replying "No, I'll wait," which makes no sense in context. It would have made more sense if Barney had asked "Do you want to leave him a message?"
A Black Day for Mayberry - S4-E7
Factual error: An armored truck is going to Fort Knox from Denver would never go through Mayberry. Fort Knox is in Western KY south of Louisville on I-65. NC is accessible mainly by going south down I-75 to Knoxville, then heading South East along I-40 towards Asheville, NC. To get to NC from Fort Knox you would need to go up to Lexington then Knoxville/or go east across the wky fka The Green River pkwy to I-75 then to Asheville. There is no easy route; why would they go through KY to NC and turn back to KY?
Answer: It was a joke. They were supposed to be dumb hillbillies.
Both. According to later interviews with both Andy and the Dillards band (the real name of the band that played the parts of the Darling children, of which Charlene (Maggie Peterson - Mancuso was also a member) the reason the Darling boys never had any lines was because they would've had to have been paid if they spoke. In return for appearing without lines or pay, Andy promised to get as much of their music onto the show as possible which, he did. This obviously gave them a lot of exposure.