Is the rear sight a target sight ? ( and if the front sight a target sight, it might be a factory target gun. ) Any serial numbers stamped on the sights ? If the evidence points to a target gun, the uptick in value would only occur if the gun letters as shipped as a target from S&W, and what that might be depends on negotiations between the parties, plus too many factors can influence the deal, such as condition and the economic position of either party. Ed. ( PS: See PM )