The Romanian sidefolder is a direct 2-screw replacement for a standard fixed wood stock, it will work on basically any Romanian rear trunnion. There are 2 types of side folding stocks- one with a lever and one with a push button, I’ve not found one type to be easier or stronger than the other so just get whichever one you prefer or whichever one you can find.
There are also East German and Polish (Tantal) sidefolders that look almost identical when mounted but require an internal mounting plate that gets sandwiched under the grip nut, it’s also a solid mount but just isn’t exactly Romanian correct.

Romanian Sidefolder on standard WASR receiver and trunnion: