No luck on Gunbroker, Auction Arms, and so forth? There was one for sale here a few months back and I remember price-comparing at the time. You might also try the Cabela's listings, they have the collectibles and nicer items listed online.

Maybe someone here has a current big 'ol book of gun values and can look it up, I think the ones at Sportsman's Warehouse are shrink-wrapped to prevent browsing.