I found a GT sitting in a yard with those same wheels.
I could tell it's been there for awhile as it's half way up the wheels from sinking into the ground!
I offered them $100 each and my wheels but they must think they are made of Gold!
I always liked the slots over the too shiny 'chrome Cragars'. The slots look more like a no-nonsense race wheel, as in Halibrand, and Cragars were...60's bling.
A nicely restored set of slots is worth something (although $500 is pushing it with old tires on them, I'd say more like $300). For the right price and some elbow grease you can "turn a sow's ear into a silk purse". But yards like you mentioned want to sell the sow's ear for the price of a silk purse...or worse all they really have is pork rinds!