What is a 73mm bolt pattern?
I'm real skeptical about buying rims and using the tires that are on them. I've done it twice and both times the tires have been junk on arrival. You don't know what they've hit, or if they're balanced or what, even though it sounds like a "buy and bolt on" deal.
I'd offer him $300 for the wheels and he can have the tires back when you mount new ones. That 5th wheel with the crack should either be tossed or ONLY used as a spare, cracks are no good.
I like them though, may not be flashy, but they're clean as hell.