As for the...additional...number, I haven't got the foggiest, as to what it might represent...What kind of tool did you use to open up the caseback?
Shrug.
- AT


the OP I and OP II are okay, not haute horlogerie ofcourse but imo good enough
scroll this link and you'll see pics of an OP II ( boutique Pam 41x)
Only look at the pictures on the left, you don't want to see the right LOL