It's hard to find parts for older models these days. There are some companies out there, but I can't guarantee quality and amazing customer service.
I think SD Truck Springs may have something, or there's always ebay.
You will be better off checking with communities based around that older generation of the Wagoneer. Often there are little nuances or thing you should know which often is found on those communities or tech's that really know these. I suggest you start their before anything else.