Hay! Ya been playin in my gun vault withergyld
I have one of each that you mentioned. I am still looking for documented info on the DP marked Guns.
Concerning the other with the rail as pictured- What I do know is that all with that type rail were imported by KSI in Pamona CA. If they were imported this way or applied later is unknown to me.
The Navy arms CC mounts will not fit that rail. In a few weeks I will have a Chinese made "Russian style" Clamp lock type mount and will let ya know if it fits. Same as the type fitted to their "Farmer's Friend" SKS in the green box. Navy Arms described the mount as " identical to German G-43 mount". The curently available Romanian scope mount for the (PSL/Romak) will fit that rail with some removal of wood from the stock and minor adjustments to the mount. J&D has them for 79.00.