Back in the early '80...SKS's would not sell here...Couldn't give them away, and, there were millions of them worldwide. During those years, the Chinese did crazy thing to some of the rifles to sell them in the United States...
One of those things was the 20 factory styled mag...and, fiberglass stocks that looked just loke the wooden stocks, except they were lighter in weight...I have seen a few of the 20 round mags. Some of them had the circle with the star inside it embossed in the metal...I saw one that has a black stencil painted on it...
I have had a couple of the fiberglass stocks..they are cool...
So, if you want hi-capacity mags for your SKS...scour the countryside...they do exist...just got to find them...
Steve