Only folders are the galili type plastic ones. Other than that you have to put one on it yourself, but of course keep in mind the us parts count to keep it 922r compliant. I suggest adding a US made muzzle device to make up for it.
Those Tapco side folders century puts on the WASR look pretty crappy in person.
I have a German set as well--I put a rail on the bottom of the of the bakelite lower, I can mount stuff to it...I was hesatant at first-- but my bipod can use the weaver rail to... its the best way to attach a bipod to an ak, I get real serious accuracy with the set up....my little rail is only an inch1/2 long so its not to abtruseve. I wouldnt even consider really using a wood lower -- the german bakelite works great, and the set cost me 19.00 bucks.