If the rifle was converted at Long Branch, there will be a mark on the receiver ring, and a serial number on the receiver ring and barrel breech. There will be no bayonet lugs. For a DCRA conversion, the proper magazine would be a .303 one, because the rifles were used for single shot, slow fire, prone target shooting. A 7.62 magazine could have been added later, but it would not have been part of the original conversion.