are the screw holes the only thing that's off?
....you're trying to use a plate for a tofu case for the case of a RK G68
... does the plate fit otherwise?
... everything line up as it should except for the screw holes?
... are you using a different pcb as well or just changing plate material? (you probably won't see a big difference going from say an aluminum plate (which i'm guessing is in the RK G68) to the tofu brass plate.
if everything checks out, put the old plate on top of the new plate and mark & drill the new holes.