Arrived last week. A cal 52T from 1927. In its branded 0.900 case luckily.
I know some 7800 pieces were made from the "tirette" version of cal 52,
and that some ( 1200 if I'm correct ) ended up as center seconds movements in
navB watches.
But I have no idea how many ended up with chronometer on the either painted
brass or fired enamel dials...