Here are some helpful comments from Suitbert Walter:
"If I'm recalling correctly about 1200 pieces werde made of this chronometer and there are some differences to mention:
-there is a small second version, which is apparently rarer than the shown sweep center seconds version
-there are two case styles, steel and silver - usually the silver case doesn't have a chrystal (the one pictured by you was later modified IMO)and the steel case mostly has a chrystal. For the silver case, non chrystal version there is a thick, large chrystal in the brass "over case".
-originally they usually don't have a "bow" as the one in your picture, but holes for attaching it. As the watch usually remained in the box the bow was obsolete.
-some earlier versions were equipped with cap jewels for the pallet as well, later ones even without the escape wheel cap jewels.
-the one in your picture has a Guillaume balance wheel, some few earlier ones had an ordinary bimettallic (brass/steel) balance wheel.
As a side note, the well known russian deck watches (differently signed, Kirowa, Poljot..IIRC)are a direct and decent copy of this 22 lignes movement. But I'm not sure if this perhaps was a licensed copy."
