Even if you found the original vendor it is unlikely they would have any of the old decals and probably cost prohibitive to gear up to make them. On my Montana they are not single decals. They are made up of various small pieces arranged to form the mountains and other pieces for the "swooshes".
You might try a local graphics/wrap company. If yours are fairly clean they may be able to take a picture and reproduce them. Or they will likely have a library of scenes that you could choose from. Someone on eBay sells, or did sell, replacement decals for Montanas. You might look there for your Forest River Wildcat.