the .3
5 caliber navy revolver with the bone grips and crossed key marks appears to be the same type described in an article in
the gun report from may 1986. Also on p.140 of
the book of colt firearms by r.l. Wilson and r.q. Sutherland, described as a "brooklyn bridge" revolver because of the cylinder scene.
Made by gunmaker antoine masereel of liege, belgium - thus the belgian proofs.
link - scroll down to "masereel revolvers colts de marine a pistons" catalog page & following photos.
Apparently yours was marked for the turkish market. Called a "piston revolver", presumably referring to the action of the loading lever.
Also sold by adolf frank export company (alfa) of germany. Alfa was the european equivalent of francis bannerman & sons in the us. Shown below is part of the 1911 adolf frank catalog describing these pistols.
it was the first 20th century copy of a colt cap and ball revolver.