Stude 1/2 ton trucks used a 5x5" bolt spacing, the same as GMC/Chev trucks. That said, most Studes (pre-62, I think) used drums that have a ridge that interferes with the GM wheels. I believe SI sells NOS wheels for your truck.
Both rebuild kits and new wheel cylinders are available for your truck from a number of vendors. Whether your old ones can be rebuilt depends on whether there's any corrosion that can't be cleaned up with a hone.