I'm assuming that this is the '47 3/4 ton in your profile. The following is not accurate if you're talking about a different truck.
Are they the stock Huck configuration?
If so, any 1946-1952 (and some of the 1953's) of the same size will work. They all had the same brake setup.
Later years, afaik, will not work. It seems like the drums aren't as wide. I checked into it when I was redoing mine.
The usual vendors (American Classic, Jim Carter, Chevs of the 40's, et cetera) all carry front drums, and you may find them at your FLAPS. They're usually a special order deal, but I've found that brake parts at mine are oft times cheaper than ordering them through the mail.
Rear Drums... Good luck. AFAIK, the only vendor who has rear drums for a 3/4 ton Huck setup is Jim Carter. The FLAPS didn't have them.
Though, on a bonus note, the Federal Department of Whichever One Deals With Car Part Standards says that you can turn a Pre 1953 drum as many times as you like. They don't care about minimum thickness on stuff that is as old as ours... At least, that's what the gentlemen at my FLAPS tell me. They've done three of mine with no problems.
I would replace them too, then.