That's why they don't give the owner's number. Washes the owner clean of the transaction and possible liabilities.
Best bet is getting that when you are in negotiation. But it sounds almost like this car has been flipped a couple times, so the last owner that consigned it may know nothing.
It's really frustrating. The intent of these people is just moving a commodity. They have no care about someone maintaining this car and enjoying it.
On the flip side. I know a guy that personally restored an AAR to a high level. It's been sold a couple times in last 3 years for over six figures. He would love to share info with the current owners... None of them care to connect with him!!!