The 'Not For Ball' mark was used only for short period and merely denotes that there is some degree of choke. It came into use shortly after the use of choke became more commonly used. A lot of these big doubles were not built by the person whose name appears on the rib. They would be made by a few Trade specialists and 'named' as required. Strong possibility with yours is that it was made in the trade but never got ordered so just went out for general sale. Not all that unusual to come across here. There may be a couple of small initials on the barrels that could give a clue as to worked on it giving a possible answer to its origins. Quite a following for these big bore guns over in the U.K. where they can still be used. Hellishly expensive loading Bismuth ammo for them though. Lagopus.....
