Assuming it's not refinished or cleaned with steel wool, that all serial numbers match, and the stock is not a reproduction or refinished and that it's really a conehammer model and still chambered in .30 Mauser then the rig should bring somewhere between $1500 and $2500.
BUT that is a lot of assumptions that can only be answered with detailed photos.
An owner's faint recollections regarding the gun are usually worthless. Just like every bubba-fied, over-polished, chrome-plated Luger comes with the statement that "Yep, this one-of-a-kind presentation Luger was taken from the hand's of an SS officer".