The Mauser's frame serial number certainly falls into the right range for a "red nine" wartime gun, everything on the frame is serial numbered correctly, and only the top end is a post-WWI short-barreled "Bolo" .30 Mauser gun. When was this top half mated with the frame? Well...somewhere between November of 1918 and when I traded into it last year.
The Luger is a short-barreled .30 Luger gun as well. While its serial numbers would seem to denote an earlier manufacture, the caliber and barrel length are definitely postwar.
See, the Treaty of Versailles and its codicils prohibited the shrunken German arms industry from making military pistols. Barrels of 4" or more and bore diameters larger than .32 were verboten as military ordnance.
So these were less-military.
The "Bolo" nomenclature for the short-barreled Broomhandles comes from the fact that the newly-triumphant Bolshevik government in Russia was having a hard time securing arms deals from foreign states until they could get their own small arms industry restructured after the revolution.
Weimar Germany, a fellow international pariah, was happy to make the sale, and the short-barreled Mausers are known as "Bolos" to this day.
Since C96's had been popular with White Russian forces and those of various separatist republics, these fit well into the nascent Soviet army. As a matter of fact, when the USSR designed its first homegrown pistol, the TT30 Tokarev, it used a cartridge that was little more than a slightly spiced up 7.63 Mauser round.
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