but I'm convinced that rads deteriorate with age not use especially on bikes that have stood for a while
Yeah...not a problem as long as there is not a problem with what is being put inside. I have been working on Ducati's as a pro for 21 years now and i have never seen a Ducati radiator that rotted to death. crash damage and holes from debris yes but those both were easily repaired. this is simply not a normal problem sio I would get a different opinion from a reputable ducati service center in your area.
If you are looking for a repair of yours try these guys https://www.motorcycleradiators.com/
as they do amazing work.
My only issue is you should be able to buy a good used radiator for your bike much closer to home and if you use a proper coolant it should last the life of the bike. Keep in mind you want a low silicate coolant, it should be right on the bottle.