Other mistake: Mainly in "Who Stole My Watch?" and 2 other episodes the the Petries and the Helpers talk about the Helpers dog, but there is no dog, the dog doesn't have a name they keep saying "our dog" or "their dog", and there's no dog house, water bowl or food bowls for a dog at their house in any episode.
Other mistake: Any time Rob has to go to a doctor or to Jerry to get his teeth worked on, if you look at the window behind him and whoever is working on him. It's the same buildings every time. Even though he goes to different doctors. Also, that window and the curtains are also the same exact windows and curtains in Robs office.
Other mistake: Laura tells Rob "oh you don't smoke!" But in several (double digit) episodes Rob not only has a lighter but also a cigarette in his hand or mouth. One episode while he and Laura are illegally about to eavesdrop he puts out the cigarette on the speaker causing the speaker to turn on and they start eavesdropping again.
Other mistake: Laura and Rob do not like having guns in the house and Laura is terrified about having them in the house... Yet in this episode... There are 2 guns in the basement displayed right next to a giant deer head on the Cross beam in the middle of the room up high. Neither of them care that the guns are there.
Other mistake: Laura tells Sally, Rob and the rest of the staff she's going to have a baby in a few days or so while she was at the Alan Brady Show. If Laura is going to have a baby she should have the baby bump the whole episode while she and Rob are reminiscing. (00:05:00)
Other mistake: Rob and Laura's old house changes from episode to episode when they go back in time reminiscing. 1: Petries and Helpers are in Rob's old house the size of that house was a trailer sized house. 2: Rob was in the Army the house was the size of a small apartment.
Other mistake: While Jerry and Rob are furious, Jerry asks the sailor "What's the matter with the lights?" and the sailor says "power failure on the line, they can't locate it." If there's a power failure then the room would be completely dark just like it is outside. Yet Rob and Jerry have shadows on their hats, jacket, shirts etc. as well as a shadow from the bunk bed. These shadows are caused by the non-working lights or the lights behind the camera.
Other mistake: Rob is complaining to Sally and Buddy about this couple running through a parking lot not looking where they are going, and they knocked him down on his rear end as well as hands. He fell into some grease yet there weren't any grease stains on his jacket which would have actually been on his butt and hands.
Other mistake: Laura is doing some work on when to have Richie's birthday, and Rob tells Laura "I thought we decided that about 8 years ago." Yet Mrs Billings has asked Rob to do 2 plays (1 each year for the PTA meetings) In the Happy Birthday... (Feb 1964) episode that would have made Richie about 10 due to the fact that Richie was 8 when "What's in a middle name" (Nov 1962) aired. (00:01:00)
Other mistake: When Rob, Buddy, Sally, Joe and Mel are all showing up after they played golf at the beginning of the episode if you look at the window all the background there is flat as heck. But trees do not increase in elevation that quickly in flat ground. Unless you're in the mountains.
Other mistake: Rob is discussing the box of love letters with Laura she tells him "they're by the furnace!" Rob tells her "there's no shoe box by that furnace." Laura tells him "they're right behind some loose bricks" well when we see the basement... There's no furnace or bricks anywhere to be seen.
Other mistake: Rob is in Captain Lebost's office. Rob has already said that Laura accepted his proposal weeks ago and they got married 2 weeks ago, and he asked for 1 3-day pass. Yet in "Will You Two Be My Wife?" he says he asks for 2 3-day passes so he could go get married.