I looked into suppressing my Yugo ~6 years ago in order to shoot subsonic handloads through it at night with my night vision. The Yugo SKS really appealed to me because it was CHEAP and already had a gas cutoff built into it. I wound up shelving the project for a few reasons.
1. I read in a couple different places that the threads on these barrels weren't always perfectly concentric.
2. The left handed metric thread pattern would've required an adapter to be made to 5/8x24 for a 30 cal can. I found a place that would do it (can't remember where now) and I think it was going to be ~$175. I thought that spending that was a bit excessive considering this was supposed to be a CHEAP setup. Also, I did not like the idea of attaching a can with RH threads to an adapter that is secured to the barrel (which may or may not be concentrically threaded) by LH threads. Tightening the can onto the adapter may start to loosen the adapter from the barrel. Yes, loctite or threadlocker would probably prevent that from happening, but still.
3. Accuracy tests w/ my particular SKS didn't turn out well (used US made factory hunting rounds) while I was waiting on the quote for the adapter. This essentially cancelled the project for me, no point in moving forward once this was established.
4. I calculated how much I'd be spending on the thread adapter, aftermarket trigger for SKS (UGLY trigger pull on mine), and some sort of stable optic mount for a night scope. I would've essentially had to spend as much on this project as I would've to do a 300 whisper SBR upper. The SBR whisper upper would've been MUCH more ideal (no adapter, already has a good rail, uses standard 30 cal bullets) and I would not then have to modify an otherwise decent C&R rifle.
5. Since I was planning on using it w/ handloaded subsonics, I started looking for 0.311 diameter 200gr+ bullets which didn't go well IIRC.
Again, my decision to cancel the project was based on what I was intending to use it for and what it would cost me to get it to that point. If your uses would be different, it may be worth it to you. As always, YMMV.