It's really obvious when you are watching historical films made in historical periods that the film is 'about' the era that it was made, as much as the era when it is set. It's particularly blatant in such matters as makeup and hair style. The Westerns of the 50s show 1950s people, with horses, the War Films of the sixties (Kelly's Heroes, say, or Where Eagles Dare) are fought by 1960s people.
There are a lot of TV shows set in the 1970s at the moment, and of course Watchmen is set in the 1980s (kind of). It's interesting to me because I was a teenager-to-adult during this period, and my memories of those days are quite different from what you see on telly.
Just as an example - during the 1970s there were flowers everywhere - Traffic islands and parks had floral displays and flowerbeds. Also the shops weren't protected by metal grilles or shutters at night. Also there were far fewer homeless people begging (in Darlington there was one guy, called Andy, who everyone knew). So public spaces were a lot more cheerful and much cleaner than you see in the programmes. A lot of what is shown as typical 'seventies' came later, in 1979 during the public service strikes, and then particularly in the early eighties with mass lay-offs and cuts.
I guarantee when they start having TV shows about the 1990s and 2000s you young 'uns will be posting on your blogs (or whatever they have by then) 'bah - it was nothing like that'.