Williams Gun Sight Co. makes W/E adjustable aperture and square notch replacements for the standard SKS. There is also a fiber optic Fire Sight front sight blade for the Williams rear sights. A W/E adjustable ghost ring rear sight called the Mojo Sight is available to replace the standard SKS rear. Last, there is the Tech Sight TS200 that attaches to the back of the SKS receiver using the take down lever holes for the attaching bolt for the sight bracket. The problem I see for this sight is you're likely to change the zero if you remove/install the sight to strip the rifle.
Bottom line: an aperture sight is a very desirable improvement for the SKS iron sights.
The peep sight makes the SKS much better. If the dead feral pig in the freezer could testify, he would agree. I'd rather take the SKS for pig plinking than my sweet tack-driver .22-250. I don't have to worry about the finish, bumping the scope, or do mil-dot calcs in my head.
I find the rifle good to 300 meters on a man-sized paper target, most of the pigs I've taken have been within 50 meters.
My young cousin, the competition shooter, can do much better with it.
I sold my AK style to help pay for culinary school. I'm still happy with that sale.
/johnny