Hi Marcus,
The origin of the revolver is from the former Austria-Hungary realm at the end of the 19th century.
It is made by the company GASSER, model Montenegrin, so it is not made in Belgium. The Belgian stamp of Luik or only because the revolver was proofed in Luik.
The original model of the revolver is 'model 1880' but those where made in 1910. The revolver on the picture is probebly 'model 1873' made in 1913. They where made in 11mm Gasser, 8mm Gasser and 9mm Steyr.
So the stamp with the two key's are most probebly from Austrian-Hungarian origin.
The stamp
ELG is
Eduard
Grimard
Liège.
The stamps
R,
L and
A with the crown are belgian stamps with the initials of the names of persons who proofed the revolver
Guy
http://guns.connect.fi/gow/QA12.html
http://www.littlegun.be/arme%20autri...asser%20fr.htm