Please- the question has an answer, don't be so literal.
Is it exact? Of course not. But it will give us an idea.
Every dealer/auctioneer can give you an approximate value of a gun - given x, y & Z, your gun is probably worth between A & B. If you don't believe me, flip through an auction catalog. These approximations are called estimates, and they're pretty consistent across certain types of guns in a certain range of conditions.
Is it always exact? No, but it is an educated guess at what an item like that will sell for.
BTW: Gardiner's sale should be done by now, so we should have the results soon. Who know who'll be right.
And check out this listing. I love it: "Original restored by Turnbull". I guess if the work's done right...
http://www.gunsinternational.com/PARKER-VHE-20-GA-ORIGINAL-BEAUTIFUL-.cfm?gun_id=100245697OWD
