GOOD QUESTION!
Don't give up on this...I think there's nothing like the old,worn paint you are talking about!
In my case, I have a 52 with dents that this working truck naturally would have. I don't care to remove these dents, but wish I had the old faded paint to go with it. The PO painted the truck with a blue metallic shiny paint. Good God!
I have been trying to find a way to shoot it with a dull mix of paint...I am even concidering an olive drab shade that looks a bit like faded forest green.
I hope you come-up with something!! wink