Re: Winchester Model 1890
One problem with auctions, on or off line, is that one or a few well-off bidders who decide they have to have something can bid the price beyond all reason. Further, since there is no validation or authentication of claims (as there is in the better auction houses), the seller can put forth any claim, no matter how ridiculous or impossible, and some buyer may accept it. (No, that M1 carbine was NOT carried by U.S. Grant at Vicksburg!)
Those are aberrations and I don't think a couple have influence on overall pricing. But if the exaggerated figure becomes "the value", then the prices of ordinary guns can go out of sight. More likely is that people will buy high priced junk, then find when they decide to sell, that they cannot get a fraction of the price they paid.