Is what MadMen depicts truly a real revelation of just what Manhattan, etc was like back then or isn't there a lot they're overlooking?

FutureMenz, it is very much what NY was like back then.  The only thing that you are not seeing is what NY was mainly made up of at the time, which is working class people in residence all over the city.  My father and his family grew up in the pre and post WWII years in the area we now know as Chelsea, 23rd and 8th ave. and my aunts still live there.  Other than that, they have pretty much got it to a "t".

E.

Elliehenne, why do you suggest that working class people were not in residence all over the city? In the pilot episode Joan says to Peggy something like 'You will live in the city in no time just like the rest of us'