They certainly used C-47's in the CBI, and it wouldn't surprise me if they used both to go over the Hump. It's just that the pressurized C-46 would have been less unpleasant, whereas the C-47 is the poster boy of WWII cargo aircraft, with much more footage intact.
In the bomber world, as I understand it, B-17's were not pressurized, but B-29's were, so B-29's were better able to do high altitude "above the fighters" strategic bombing of Japan, whereas B-17's flew at fighter altitudes and relied on having about 10 .50 cals.
The C-46 was a passenger airliner too, before the war, just much less successful, and a Curtiss instead of a Douglas.