I'm in the process of doing the same thing, I have two young daughters who love going Jeepin. Jeep use to sell an upgrade kit, but is difficult to get now since they dropped the XJ. If you can fine the Jeep upgrade I'd grab it. If not I would try a salvage yard with a good selection of Jeeps. Mine came out of a mid 90's rig with approx. the same interior color. Get both pieces of plastic that the belt runs through to use as templates to cut for the belt location on your rigs or use the newer trim panels if they match OK. The top bolt to the rear belts goes into a nut affair that will need to be attached to your Jeep. I riveted in the pulled one then welded the center section for good measure. It is a real pain to pull out of the donor vehicle, I used a chisle and a big hammer to break it loose and finished the job with a big pair of ViceGrips along with a fair amount of skin from my knuckles. The torx bolt that hold the belt clip below the seat is really a bear to remove also, the nut is staked so it doesn't come loose, and it works good. If you can get a good sized ratchet set up with the corrrect torx driver it'll be a big help. On the plus side, your Jeep should have all the holes in the where the rear sholder belts bolt to already drilled, my '88 did. Good Luck
Woody