Vern, my method does apply to rifles but the population is small and so it is less specific. The "market" values the Lang name at BV2 which is 3/4 of the value of a BV1 (Boss, H&H, Purdey, and Woodward). The photos would appear to me to show a best work hammergun - OQ5 (hammerguns value about the same as boxlock ejectors). The Current Condition appears to be CC3 (significant use). Putting these three factors together in a 3D pigeon hole table shows BV2-OQ5-CC3 = $4,722 for a SXS shotgun. Now the catch 22! SXS rifles value higher than SXS shotguns. How much? Mmmm, depends. High grade hammerless rifles may go 4X similar shotguns while lower grade hammer rifles may go only 2X; BV2-OQ5-CC3 X 2 = $9,444 And there are those blacked damascus barrels (improper restoration). It would be reasonsble to "ding" the CC level by one point (CC3 down to CC4). That would make the value for a shotgun at BV2-OQ5-CC4 = $3,594 and a 2X rifle at $7,188.
IMO, this rifle deserves a bit more than 2X and doesn't deserve a full level reduction for the blacked barrels. The asking price seems reasonable for a highly reputable dealer.
Note that value is theoretical. Price is the amount agreed to by a willing seller and a willing and able buyer. You could, IMO, have the barrels restored without any further drop in value. However, you might not recoup your cost of restoration at time of sale.
Hope that helps you. Feel free to ask any additional questions.
DDA
Last edited by Rocketman; 10/25/18 08:51 PM.