Most of the cases, the stock were installed after receiving the parts and only part of the serial number were pressed on the stock. The smaller factory, usually have 4 digits code such as #9821/#5017, most of them does not have a marker stamp(works like branding today) and therefore no stamp on the gun, only the serial number. The parts they sent out are never stamped with any maker's stamp but only the serial number because they don't know which factory will receive them. so, factories like #216/#356/#296 will produce the major parts and sent to them for assembly.

But,those factories are not capable to produce major parts like barrel/receiver/hammer etc. In the history of chinese SKS making, during the 1950-70s, a lots of smaller size manufacturers were set up at remote countryside to prepare the potential war between China and America. I have put less than 100 rounds thru it just to function test and it ran great, no malfs, and much more accurate than i was expecting.Just to share some info with you and may this help. Blue is good, all around, no rust/scratches, bore is bright shiny & looks to have hardly been fired. All the components (stock, bolt, dust cover, trigger guard, & magazine) have matching serial numbers (last 5 digits), and the stock is in far better condition than most SKSs I have seen at gunshows.rather nice in fact.very minor flaws and a deep rich finish. I'm trying to come up with the market value for the rifle as I want to sell it. I did some online research but got nowhere with this particular '636' factory, other than a thread where some guys were saying they made good rifles. Picture worth a thousand words, attached. It looks like there is a number 1 (or a long vertical strike mark) preceding the serial #by enough distance so you know its not part of it, and a larger font 'O' after the serial number. Guys I have a Chinese SKS with '636' in the triangle factory stamp, and serial # 22045367.

Norinco sks year manufactured