I am a long-time reader who is at last able to offer a humble contribution to this excellent forum.
A good person to speak with would be Dr. Richard Polt of Xavier University, who is also an authority on historic typewriters and runs the popular
Classic Typewriter Page. He is well-connected in the typewriter collecting community and he might be able to find an answer to your question. His e-mail address is on the website. I hope that this is of some help.
For some of us, an antique typewriter is just as much a thing of beauty as a classic aircraft!
LTAfan