From what I can tell by looking at the FAM diagram for the '54 frame, the rear cab mounts are similar to the front mounts (rubber donuts and thru-bolts) instead of the shackle type rear mounts on the 47-53 body. A couple options come to mind for what you're considering.
1. Drill and reinforce the floor of the 47-53 cab for the later style rear mounts.
2. Remove the later style rear brackets from the frame and drill for the shackle rear mounts for the earlier cab.

I think #2 would be the easier route if you wind up with an earlier cab.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.