Interesting gun, indeed. I made some assumptions and applied my formula. Assume the gun will value similarly to a "typical" sidelock of original quality grade the (OQ3), T. Andrews is brand value three (BV3), and the current condition is properly restored (CC5). BV3 - OQ3 - CC5 = $3148. Assume nobody interested in this class of gun is willing to accept the replacement barrels as a proper restoration and we get CC6. BV3 - OQ3 - CC6 = $2320. That puts it in the price range realized. Make it a CC 6 1/2 and you are right on he button.