Oh YAY! I am so excited, feed drop, reverse! Now it really feels like a super-find! I just got the motor going and found a manual in English-- we are gonna make some stuff! Thanks so much for your feedback-- I may never know her full history, but having the manual and what appears to be a receipt of purchase is quite nice.
The closest thing I've found the to numbering you mentioned on the manual is in the front page lower corner. It reads "Form. 2741 ung./136." Ung would be short for "Ungarisch" or Hungarian. Maybe 136 is January 1936? The receipt I have shows a purchase date of January 11, 1949 paid in three installments.
Thanks again for you help! I am so excited to learn free motion quilting!