A document that feels appropriate to add to this post.
A 1949 ad - stating the results from the 1948 Chronometre contests...
Notice the number in the ad: 464254 and 464260.
Then look at the number of the the movements in your post!
464254 - it is the same movement as you have pictured in your post!!
"464254 obtained the only award attributed for the smallest mean daily variation in the pocket chronometer class" !!!
People, we are looking at piece of horology history here!
The other two: 464267 and 464272 - so, from 54 to 72 is 18 numbers.
Best
Blomman