1. Will SKS top covers work on any SKS or are they country specific? I own a like new 1979 Chinese SKS and don't want to modify the original in case I want to return it to original condition.

2. Does anyone mill or grind a SKS top cover flat and drill and tap for a low mount Picatinny rail? I have shopped all over for a low scope mount and haven't found a single model that I like.

My goal is to mount a Primary Arms micro just as close to co-witness as possible. Virtually everything on the market is too high or butt ugly or gas tube mounted. Even the rear sight replacement rails are higher than I want.

I tried to make a cover fit well enough on my SKS to mount a scope on, I failed miserably. You may be able to do it,I can't.

It's not going to work the way you want.
The sks top covers are interchangeable, but won't hold zero due to play.
The only real solution is a side rail. Your best bet is to get good with the iron sights.

Issue sights are useless with over 60 year old eyesight. I mounted a rear of the receiver ghost ring and it's better.

I don't feel a SKS deserves a scope because I consider it a <150 yard rifle. I do not want to drill and tap the receiver.

I guess I'll try the rear sight mount rail next.

Top covers are basically the same except Yugo, and Yugos just need the forward corners rounded off a bit to fit the rest. As far as <150 goes... https://youtu.be/1c7ZTcNTC5s?t=386

Well this fix isn’t for everyone but my SKS came in an ATI Monte Carlo stock so I found a Tapco replacement top handguard from eBay with the pic rail molded in and replaced the one on mine. Mounted a TRS-25 red dot and it holds zero just fine out to 100 yards. Not pretty but it’s solid.

I’ve also done the same with the factory top handguard on a VZ58. It’s closer to an SKS setup than an AK. I picked up a no name pic rail section from Amazon, filed the back to match the curve of the handguard ( that’s most of the work) then drilled two holes for bolts. The bolts I used were a bit too long and interfered with the piston so I just used a Dremel to grind the bolts down til I got clearance.

If you want to try refitting an AK handguard on your SKS both Command Arms and Hogue make handguards with rails molded in like the Tapco, although none of these are available by themselves but if you can find one used it will be cheap. I know my Hogue AK handguards came with both a smooth and a railed top piece.

Downside, you lose your iron sights. I think the Tapco SKS rail and the Hogue AK both had a groove down the center so if you pulled your optic you could use irons.