A buddy has a cover-mounted scop on his WASR10; i take my boresight every time i go visit. The thing is too easily jarred off zero & has to be removed for basic gun cleaning. I had a receiver cover-mounted scope on my SKS; it was so irritating that i just removed it. I am looking for one of those side-mounted, quick release scope mounts (AK style) currently.
The SKS forum i visit recommended this place for my search Optics Accessories - Side Mounts - Kalinka Optics WarehouseÂ® .
Good luck with it, whichever way you end up going.