How much interest is there in 1960-62 Valiant parts?

I have been dealing with 70 and later A body stuff. 68 and later B body too. That stuff is what I am familiar with. These cars are as familiar to me as Citroen or Soviet era Lada models.
If you are trying to politely tell me that I shouldn't post threads like this...well, what is a fair way to determine value of an unfamiliar part when a person can find no history of similar sales?
I know the value of a 8 3/4" axle, a rebuildable 340, Duster fenders, etc....but who here hasn't seen an ad with a price that seems way too high? I don't want to be that guy. A 70-72 Duster door can sell for $300. Is anyone going to pay that for a 61 Valiant door? I rarely see these cars at shows and haven't seen one on the street in a long time.