radiators still fail; quite a few have had a number of replacements. Tank is not something I've ever seen personally, or heard of from any friends first hand, and I belive it is avoidable buy using regular fuel and if storing do so with an empty tank.
You could try DUK and ask if its been done, or maybe another delaer to look up service history thru the warranty system?
Its a used bike tho, yer pay yer money, yer take yer chances
worth noting these are not recalls; at best they are reowoks but most dont get done until they fail