Writer James Fritzell didn't like Aunt Bee's line about the war picture in which the Nazis were killed on their motorcycles. He felt it was out of character.
The gag in which Barney's motorcycle takes off, leaving the sidecar behind, was borrowed from The Marx Brothers, who used the same gag in Duck Soup (1933).
Barney's goggles containing no lenses was a common occurrence in eyewear on film at the time, so as to avoid the reflections of the camera, studio lights and filming crew. This is also true when it comes to mirrors, windows or any reflective surfaces. When mirrors and windows are involved in a scene, the camera will be at an angle to the surface, so as not to pick up its own image.
The motorcycle was not an "RJ 300 Motorcycle," that being a made up designation. The bike was actually a 1927 Harley Davidson JD model.
Writer James Fritzell said that the long description by Mrs. Beggs about her sister Tilly was created to illustrate how women remember details differently than men.