I agree that TV shows and movies are full of incorrect props when it comes to furniture, appliances, cars, etc. I find "American Dreams" to be a joke. Just watched it for the first time last week since the series started. Yeah, what TV store owner wouldn't have the best color set around in his own house? I grew up down the street from the local Chrysler dealer and they always had new cars on their driveway. But also, what TV store owner was rich enough to buy his kid a brand new Mustang? As a car fan, I see mistakes all the time. Too many cars that are brand new for the time, as are the hand-me-down type cars that kids would be driving. My sister works in film and one of the movies she worked on was "The Long Walk Home" and she sent me polaroids of the cars they were using (this was well before digital cameras) and they did a nice job. Had to take the polaroids so they could position the cars exactly the same way for the next day of shooting. I don't know who the film makers get these days to provide them with their props, but it's obvious that nobody takes the time to check their work, or they just don't know any better.
Also thought I'd mention that at the Petersen Automotive Museum in L.A. there's a vignette of a suburban garage with a 60's car in it, and up on the shelf at the back of the garage sits a table top bakelite Admiral TV. I think that's pretty insightful of them to have duplicated the situation that likely existed (and lucky for us TV guys still often does) for many obsolete or non-working sets from the late 40's & early 50's.