I recently acquired this model 1907. I noticed it doesn't have a serial number in the normal location. It does have a stamped number (18) but it doesn't look like a factory stamp. Maybe original number has been filed off? Can anyone help me with this concern.
https://lh6.googleusercontent.com/-o...h715-no/11.JPG
https://lh3.googleusercontent.com/-Z...-h691-no/4.JPG
https://lh5.googleusercontent.com/-f...-h686-no/3.JPG