Available reproduction parts are limited to hardware, brushes, rear covers, and projectors. Many parts are similar between the 5 different manufacturers but not the exact same in many cases. There are plenty of originals still out there if you know where to look. Articles about all the different horns can be found in both the Restorer books from MAFCA and the Technically Speaking books from MARC. Several manufacturers changed their products during the four years and some made several changes. The more research, the more you will know about yours.