Archie and Betty are shown as living in houses next to each other, but in shots of their houses, Betty's address number is 111, while Archie's is 2037.
Geraldine's Volkswagen Beetle in this episode appears to be a white 1957 (Oval Window) model. In the earlier episodes, and as seen on the poster, her Beetle is a gray circa 1971 model.
@ 15 mins when Miss Grundy and Archie are watching a movie, with each camera angle her hair is either tucked behind her ear or falling in her face. It changes each time the camera angle switches back and forth.
At 01:54- Ms. Grundy, the music teacher, is obviously not playing the cello. Which brings us to: Hollywood cliche #047: actors cannot be taught the few motions required to "act" like they are playing a musical instrument.