Actually Dorleac was very close to the caliber answer, but Grandveneur was closest for the date.

Dorleac wins the right to give me a deep discount on his inventory and GrandVeneur the right to give me an invitation to a hunt in Alsace.

Sincerely, you guys are champs!

Francotte 88159 is listed in the regular sources at 1936.
The proof marks concur (o):

The real find here is a photo of the ledgers that came with the weapon.

The rumor is that these ledgers are now probably lost for good.

These show among many other things that the engraveur (Cor) is likely Lyson Corombelle.

WC-