Unfortunately, Mike is right; the collector value was ruined when the gun was plated and the guns are common enough that paying to try to restore it would not be practical. Since the gun has the takedown lever (looks like the M1911 safety but isn't a safety) it is in the first B series, or second group of pistols made fairly early in the German occupation. The Waffenamt (Army Weapons Office) acceptance stamp should be WaA77 (what looks like a 4 is probably the capital "A".
The marking is actually F. B. (Fabryka Broni - weapons factory) RADOM VIS Mod 35 Pat Nr 15567. There may also be a marking "P.35(p), which was the German number in their logistics system. The "(p)" indicates the item was originally Polish - "b" indicated Belgian, "f" France, "e" England, etc.
The VIS is often thought to be an abbreviation for the Vistula River, but that is not true. It originally was supposed to be "WIS" for the designers, Wilniewczye and Skrzypinski ("i" is "and" in Polish) but the Army changed it to "VIS" to signify the Latin word for "strength."
Another story needs debunking. That is that the gun was designed by engineers from Fabrique Nationale in Belgium, and that FN engineers supervised the factory. There is even a charming story about an FN engineer escaping from Poland just ahead of the Nazi invasion, smuggling the blueprints under his shirt (one version has a beautiful female German spy, but that has nothing to do with the pistol). Nonsense, of course. The design and manufacture were totally the result of Polish engineering. Design started in the 1920's and the gun was tested in 1931; FN had nothing to do with it, though the Polish designers did have access to the Colt M1911 and some early FN pistols, but not the famous High Power.
The pistol was a favorite of the Germans, being highly reliable (unlike the Luger) and very accurate. Some were made specifically for the German Navy. Almost all in this country were GI bringbacks; there were few other imports. A small number were made in the 1990's but are extremely rare in this country; there were also some stocks made at that time, similar to the BHP holster/stock. Until that period, no shoulder stocks were ever made or issued, even though the earlier guns were all made with a stock slot.