Over lunch, I took the radiator to the auto garage across the street from Danger. The mechanic looked over the parts and said there was nothing he could do about the bolt: the remaining aluminum is too thin to rethread. He’s going to do what he can with the radiator, though.
I’m looking through parts schematics, and the part number for the same part on the Bandit is one digit off from the SV’s part. I’m going to take that apart tonight and see if the SV can use the Bandit’s bolt and save myself $60 for a new bolt.