welcome to the garage .... it may be that the Chev and GMC inners are slightly different, but most of the vendors list them as the same, like
American Classic, who have pictures you can check, usually there's some "fitting" required with the repro sheet metal .... look in the links section, there's suppliers in CA you might be able to check with, and try a post in the 60-66 forum for a more definitive answer - you could always try a post in the parts wanted for good used, lots of folks from CA here, you might find some near by with spares
good luck with the resurrection, and we'd love to see pics if you have some to show
Bill