Bob Adler in N.Y. state has a restoration business specializing in AD trucks. He has done a lot of research on paint colors and for $20 he will send you a nice packet with some reproduced color paint chips. They are reasonably close for reproductions of 50+ year old chips. He also includes some of the formula numbers. And in general he is most helpful when you call on him.
His number is: 518-733-5749 or his e-mail is:
[email protected] Hope this helps.