The 3200 and 3600 have the same wheelbase. There wasn't a "1 ton" spring option for the 3200 or 3600. There was an HD spring option for both, but neither used the 1 ton parts. The 1/2 ton HD spring (both 3100 and 3200) was simply the base 3600 8 leaf spring, and the HD spring for the 3600 is a 10 leaf single stage. The 3800 1 ton uses a different spring setup, with different shackles and hangers, 8 leaf single stage for the base, and 8 leaf main with 5 leaf auxiliary for the option. If you're has auxiliary springs, they most likely are an add on aftermarket part.
If it were a 3600 originally, it should have 8 lug axles, plus the frame number should identify it, too.
There are no lockers available for the original rear end, and the factory Positraction axles, Spicer 45 first offered in '59, are extremely rare. There was also an Eaton Positraction that will fit the original differential, offered from '60-'62, but it is just about as rare, I've only seen 1 in person, plus 1 on Ebay.
While I do agree with zmaxmotorsports that it is an awfully nice truck to alter, another option that sapping cabs would be the swap the axles and running gear to the original frame. That will keep all the body mounts and wheelbase dimensions where they are supposed to be. The stock frame will be more than adequate for that use.
