I came across this on a watch on sale on the 'bay by a fairly reputable dealer, advertised as being from a watch from the 1930s. It looked a bit similar to the 12-120 to my (untrained) eye, but found the typeface a bit odd. Gut feeling is that it's not actually from PP, but given I'm a noob at this, any advice as to authenticity would help - thanks!

 

Hey N,

it looks to be pre cal 12-120 to me, and a smaller movement (18mm) made for small watches. The size of the screw and crown seems to be the tell (they look pretty big relative to the movement). I remember reading about them being cal 8 (Edited: I can’t find the link on it will keep digging) and I used to own a watch (actually more for wifey) with this kind of movement.

have added the cal 12-120 here, I have been trampling with the latter for years to get a proper swan neck regulator. It also hints at the picture in your post being smaller relatively (by the proportion of main bridge for instance)

 

Thanks E! I was also wondering whether it was a predecessor to the 12-120. Thanks for the really helpful info about it from a smaller watch - it aided my decision making.

 

It has PP DNA, if not the high quality we expect now days.

I suspect it's a Caliber 8'''.