The pistol is a Belgian-made Montenegrian revolver. The link I provided above I believe is a 1913 date stamp below a Persian crest. There is a similar mark on broomhandle Mauser pistols that were sold to Persian around 1910 (
http://www.mbi.ufl.edu/~papke/curios/persia.JPG). The other marks on the pistol include the usual Liege proof, and the typical Belgian Crown R (rifled) proof, as well as a "Crown L", "a Crown AM" proof and what could be a Star AL or HL. these later three are probably just inspection proofs with no special significance. The only words on the pistol are "VERO MONTENEGRIN". Below are links to pictures of the other marks:
http://www.mbi.ufl.edu/~papke/curios/Montenegrin03.JPG
http://www.mbi.ufl.edu/~papke/curios/Montenegrin04.JPG
http://www.mbi.ufl.edu/~papke/curios/Montenegrin05.JPG
http://www.mbi.ufl.edu/~papke/curios/Montenegrin08.JPG
http://www.mbi.ufl.edu/~papke/curios/Montenegrin09.JPG
By the way, for people who do not know the story of these pistols: around 1874 Nikita 1, the King of Montenegro, mandated that all adult males in his kingdom should be well armed, a novel form of gun control, and that each man should own at least one Gasser Montenegrin type revolver. At the time, Montenegro was part of the Austro Hungarian Empire, and most of the guns sold in Montenegro were made by the Austrian firm of Gasser, of which King Nikita was a stock holder. Supplemental guns were also supplied by several small Belgian manufacturers. Montenegrin revolvers fired one of the largest pistol cartridges ever designed, nearly 50 caliber, with cartridges an inch and three quarters long. The design of these massive guns was rather primitive compared to other contemporary revolvers, but nonetheless the national mandate kept them in production up until World War 1. However, I have never hear that they were imported in any number to Persia. Below is a link to a picture of the pistol.
http://www.mbi.ufl.edu/~papke/curios/Montenegrin01.JPG
Cheers,
Marcus