Can we change Mafia Graves's shotgun model to a sawn-off double barrelled?

http://i.imgur.com/SqPsT8u.jpg

It already doesn't make sense that he's using a shotgun with a drum magazine which has multiple rounds in it, yet can only shoot 2-3 at a time before reloading. It would make more sense if he had a sawed-off double barrelled shotgun. Even the mafia called double barrelled shotguns Luparas.