I too have noticed that at a certain point in TV and movies all phones had the ring of the 500s. This continued well into the 80s, even on a Magnum PI the other night the obvious mid 80's cordless one guy had rang like a 500. Purty interesting.
And I concur about noticing that in old movies, especially stuff from the 50's and 60's, you will see a lot of older phones, candlesticks, 102s, 202s, 302s and AE stuff, in common usage still. My 354 was in use at least until the 70's in this house, and maybe longer, so that was 20 years and I'm sure that was an easy mark for the old phones to reach back in the old days. Of course now the 354 is 57 years old and still works just fine.
We watch a fair amount of British TV, especially murder mysteries and such, most of it new production shows, and I'm often seeing old rotary GPO 700s in scenes set in old homes or shops. Maybe they are still in common enough use to be that obvious, or maybe the set directors are adding them to get atmosphere.