Terry may have explained the information but lots of new owners here. What we need is a post at the top of this forum which says "NEW OWNERS READ THIS FIRST", but I digress.
Our coaches are what are called "custom" WRV contracted with several companies to build custom parts for them, the chassis is not over the counter so to speak, it's a custom chassis, PEAK, so trying to get freightliner or Spartan to fix it won't work.
When they went out of business those same companies may have done so as well. At the auction, all the spare parts were purchased by various individuals and companies you might find one here-Burke Morgan, 509-961-0996. As I believe he purchased all the rebuilt-new design radiators at the auction.
Otherwise you are going to have to have a custom radiator shop fix/rebuild it for you. Macs Radiator in Portland, Oregon can do an excellent job, many owners have had them fix and rebuild the radiator for them.
Do a search here on the rubber mounting brackets/bolts to prevent the radiator from shock of going down the road. There is a post here about how to build the mounts and how to put them on. I purchased extra parts when I did mine, and if I can find them I want 30 dollars for each assembly. You will need two of them I think. Find that post and you can make up you own mind. If it came with the rubber parts you don't need mine.