Other mistake: When Ralphie and Flick are walking to school for the first time, they meet up with Schwartz, coming down the steps of his house which appears to be two houses down from Ralphie's. Later, when Ralphie is lying in bed after the soap in the mouth scene, the narrator (older Ralphie), states how "Three blocks away, Schwartz was getting his."
Other mistake: When Pierre Andre is giving the members of the "Secret Society" their message, listen carefully. The first number is 12. Towards the end of the message he says 12 again. Since the first letter of the first word is "B", and there are no other "B's" in the entire message, I guess this is another one that slipped by the editor. They also say to set pins to B2, so 12 can't be B.
Other mistake: When the leg lamp is set up and turned on, the entire leg lights up. Trouble is, when you first see it, you can see there is no light in it, nor a fixture. Later, after it is broken, you again see no lighting of any kind in the leg. I don't think the light from its position on top of the leg would have illuminated the leg all the way down to the shoe at the bottom.
Other mistake: When the father "won" and he tells the family it was going to be sent "on tonight", he accidentally closes the door on one of the hound's ears. The dog starts moving up and down, which means the ear was thin enough to move around. If the ear was thin enough to move around, the dog could've just pulled itself out. (00:25:30 - 00:26:00)
Other mistake: When dad comes home with the telegram saying that he won a "major award", look at the car. There is snow piled up on the top of the car, the windshields, and the hood, at least an inch thick. Even then, the hot engine would make the hood warm up, and in turn, melt at least some of the snow. And the windshields look like there was enough snow removed to guide the car, instead of removing as much as possible for safety. It looks like the car was simply pushed from off camera.
Other mistake: When the old man screws in the blue light bulb on the Christmas tree and the lights go out in the house, the living room remains dark while he changes the fuse. Meanwhile a fire is going in the fireplace, so the light from the fire would cast some light into the room.