I wondered about the "1D" because it looked to me like a #1. You are probably right about a new door as a replacement. As for the 4D, I would probably use it if I were to get it. I like the challenge of using old stuff like that. I would love a 3A, The film is still somewhat available, I have about eight rolls of 122 film, Verichrome Pan. I am using it in my postcard camera. It is a PITA to put on a reel for development, but I did manage to adapt a Unicolor reel to take the 92mm wide film. When I run out of film I'll look for some aerial film to slit and rewind onto 122 spools. I still have the backing paper. Very careful with that stuff.