That video is overbrightened, the grips aren't that light, but ain't very dark either:
YouTube - 44 Minutes (ALIEN)
Most woods are fairly light colored when unstained. The wood you saw on my short AK is plywood, and it looks to be lightly stained, or possibly just clearcoated without staining. It came to me this way I have not done any work on it. The darker wood on my AKM was first sanded, and it was really, really blond, almost white.
My suggestion - get real Romanian foregrips and modify them to fit. They're dirt cheap in the states (order online or visit a gun show), they are plywood, and you can sand em down and stain them lighter. Doesn't get any more realistic then that. Can't really get a realistic pattern on the wood without using actual plywood.