Well, you've got several options... and none of them are inexpensive to do the job right.
1. Change Doors to the earlier "screen door latch" types, loosing the paddle door latch.
2. Install later model OEM Pillars into the 80 CJ tub.
3. Use fiberglass Tub Kit latches.
On the earlier tubs the body stiffener is a peice of metal going diagonial up from the wheelhouse to the rear of the door opening lip.
On the later tubs this stiffener has been replaced with a "B" pillar that also holds the seatbelt recoil assembly.
So you're choices are:
a. To replace the pillar ( 20 or so rivet welds)
b. Install the Fiberglass door latch kit for a flat tub wall and re-attach the seat belt to the flooring (don't forget to reinforce the mount area.).
IMHO, I'd install the OEM pillar to update the tub to the later standard and then install the OEM or aftermarket latche assemblies.