OK I have no pix as of yet, but when I get my 90 Pioneer back in possession, I will take the pix as I do it to that rig and re-write this.
As for now, I see Jeepers buying seats from other Jeepers and having them shipped at great expense. I assume this is because the typical XJ has collapsed right side foam on the driver's seat and sometimes a tear or two also. Here is an alternative.

This is from memory so please bear with me. The process is simple but a little time consuming and some of it is a PITA if there have been spills on the seats so fabric sticks to the foam. Price is right though!

OK Take both seats out by unbolting them from the floor.
Unbolt the rails from the bottom. There is a strap at the back which will need to be undone. Unscrew the retaining screws that hold the covers on. Then just start peeling the fabric off of the foam. The seat foam bases are identical, so the passenger side will fit on the driver's side, assuming you want the support back. If you have spare seats, just mix and match at will for you and your passengers support and/or comfort.
FYI, if you do need a replacement cover, it is easier and cheaper to have it shipped rather that shipping the whole seat.
Just do the reverse of the disassembly to finish up, and bolt them back in.

Yeah, this isn't extremely easy to follow because I suck at explaining things, but I think you all can figure it out as you go. It isn't hard.

The reason I know how easy it is? I have done it 3 times now to fix a sagging driver's side foam. If you go to a salvage yard to get a seat because of your foam, get a passenger side, (and the color etc. of the cover doesn't matter at all, assuming yours is still OK). Less wear on a passenger seat and the foam is always better. I am pretty sure there is one part of each sides cover, either the back or the bottom, that isn't interchangeable side-to-side, but I don't remember for sure at the moment. (Getting CRS lately)
Check that out before re-assembly.

Good luck!