Sorry, I've been away from the site for a while. Here's the answer to a couple of the above questions:
The object up by the top of the door is a decal that was placed on the original truck by the original owner--a Chevrolet dealer here in MN. It was the dealership truck from 1938 to about 1970 or 1972. Because it was originally put on by the dealer, I thought I should preserve it, so when doing all body work and painting, I carefully masked it and preserved it.
Second question: yes, as I understand it, the rear door stops changed from 37 to 38.
Thanks,
Jim