This one may have been made by Antoine Masereel or Ronge of Liege, Belgium. All three makers used the crossed keys as a maker's mark. Believe it or not, this one is actually prohibited. The proof marks are bogus, as these makers did not bother to have their guns proofed. They were made almost exclusively for export to Belgian / French colonies until the 1920's and therefore impossible to date. IMO not worth restoring. The quality is generally crappy, and being prohibited, it may get you in more trouble than it's worth...