When I first started shooting I ordered a SKS then sourced out a supplier in the USA for a spring mod kit. Then I did more research and realized all that slam fire fear was silly. Clean your gun. Check that the firing pin easily moves back and forth with the tap of your finger. Pit your rifle back together and shoot. Next time you clean it make sure the pin moves. If your paranoid check it before every shooting session.
Rifles made after 1950 in Russia by standard manufacturer specs has a free floating firing pin. Less to loose, clean and replace. Millions of them are made to shoot without the spring I think the Rusians knew it wasn't necessary.
This. To check mine, I open the action, point the barrel down and push the firing pin in with my finger. If there's no resistance going in, and it comes right back out when my finger is moved, I know it's not stuck and it's safe to use without fear of a Slamfire.