FormativeWand

Hi, I'm new to the Saiga 12 world and my ignorance will soon shine through. I as have a question about the threaded barrel and its role in 922r compliance. My Saiga 12 came out of the box with a threaded barrel. I'm wanting to add a Tapco T6 stock and pistol grip. For the sake of getting my facts straight, will this addition combined with a US mag and my existing threaded barrel stay within 922r compliance? Also, anyone know where I can get a good US gas piston ("Puck")?