I didn't think that the Russians had directly released anything and it has all come out of the Client States, Finland or the Ukraine.I have one, a 1945 Izhevsk, that was a Vietnam bring-back. As to where all the others are, well some were dispersed to various client states and movements (like the one i have, eh? probably got to Vietnam via China, but may have been direct to Haiphong on a boat from Mother Russia), others probably still sitting in storage facilities.
By the time things loosened up enough for the Russian beasts to be selling us things, the import criteria requiring a safety had gone into effect, and the Russkis probably figured it wasn't worth it, easier to just hold them as war reserves while they sold M-Ns and M1895 revolvers that did NOT require any modifications. Speculation, but based on consideration of varies facts on the ground.