In my opinion the gun was made by W.& C.Scott,as a wholesale offering for the retail trade.Scott,s would, on requested engrave the name of the retailer on the gun. Others have suggested that the gun may have been sold for retail by by William Parker, a gun stocker, operating from 50 Potter street,Birmingham ,circa 1861. This is a distinct possibility,however the engraving on the rib of;"London Fine Twist" suggests to me that the gun was made for export as this legened is seldom seen on guns intended for the British market.The most likely export destination being the U.S.A.
As to value;the 1891 W.&C.Scott catalogue shows that muzzle loading guns similar to the gun illustrated, were still on offer. The price range was 2.5- 3.5 pounds stirling. This is approximately 5% of the cost of their best breech loading guns of the day. I would expect to find guns in the condition of the specimen illustrated at gun shows, priced in the $3-400 range.