I know I could tease an answer to this question this out of the archives. I originally researched this question a few years ago. I am picking the project back up after a few years, and I am not sure I trust my notes.
I am about to reattach the shell of a 1963
Bambi to a new "C" channel and belly wrap. In my notes, I have that the original exterior rivets are 1/8" diameter, but with a somewhat oversized head, when compared to current rivets.
The closest rivet currently available, that will match the original is a 5/32 diameter.
Can anybody confirm?