Other mistake: In a hallway scene with Wally, Miss Canfield, and Mrs. Rayburn, the principal comments that "he's in the 8th grade." If that was correct, that would mean that Wally would be in high school the following year. And with 5 years to follow in the show's tenure, that would mean that Wally wouldn't be in school by the end of the show. Unless, of course, he stayed back 2 years. (00:10:10)
Other mistake: The opening credits for season 5 show June coming out of the front door with a pitcher of what looks like iced tea, and calling for Ward, Wally and Beaver who are all working outside. But the door opens by itself as she comes out, and then closes by itself behind her. If the entire family is outside, who opened and closed the door?
Other mistake: In the opening, when they get into the car, it's obvious that there is no glass in the rear window.
Other mistake: In season 1, we learn that Beaver is in 2nd grade-Wally in 8th. So by the end of 6 seasons, Wally would be in college. Tony Dow and Jerry Mathers are actually 2 years+/-apart.
