Well, I found my FGC-1 manual but it is later than the 1943 Western Electric typewritten ones abstracted on my web page at

These came from Duncan Brown some years ago

The one I have is August 1952 TM 11-356 which supersedes the 1943 edition and is typeset in typical TM fashion. One interesting addition is that when radio frequencies in the 70-kc to 500-kc range are used, a frequency shift of 170 cps is used which necessitates replacement of the M and S filters to 2465(M) and 2635(S).

You learn something new every day, huh?

Cheers,