If you are lucky you can find the paper broadcast sheet taped to the top of the glove box, under the back seat, or under the carpet in the passenger side floor board.
Personally I don't worry about what the car had when it left the factory. Any factory hd suspension components are going to be tired by now. Am radio would likely have died. 47 years is a long time and many parts can changed. For me it comes down to what the car has when I get it and what I would like to do to it to make it a nicer car. To sum it up paint it a color that you like.