Did a little more reading on this. I think yours may be the AKMS-U also. Besides being nicknamed krinkov it's also called AKR. It lacks the standard fire-rate reducer system. It also has a folding U-section butt with three rivets and a single long flute on each side. Omitting the cleaning rod allows the short, finned expansion chamber on the ultra-short barrel to be fitted with a conical flash hider. The front-site block has been moved back to abutt the laminated wooden barrel guard, and a chequered plastic pistol grip is used in conjunction with a short wooden thumbhole foreend. The sling attaches by means of a D-ring to a bracket on the left side of the front-site block.
The base of the rocking-"L" back sight is combined with the receiver-cover pivot, the sight being regulated for 100m (marked with wht looks like the pi symbol) and 500m (marked '-5'). Adjustments to the point of impact can be made by rotating the front sight.
Above info from Kalashnikov Machine Pistols, Assault Rifles and Machine-Guns, 1945 to the Present
by John Walter
You should be able to find more info and links at www.kalashnikov.guns.ru