According to Boothroyd the buisness of Manton was taken over by WR Wallis .John Wallis contiued the buisness into the 20C. They had guns made in Birmingham bearing the Manton name . My guess is that it is a gun made and sold as a Manton. I have seen several guns of this quality signed "Manton" . Buy the look of it a wall hanger is all it is .