The screw holes on the top of the tang are NOT pre-drilled, and the required drill bits are not included. This only attaches to one of the two rear trunion screw holes, as well, and uses the pistol grip nut as its second mounting point. The screw hole for the pistol grip nut is improperly placed, so the stock cannot fit flush with the back of the receiver when installed unless you open it up significantly with a drill. The handguards are also a bit ugly, but I didn't use them so I didn't really care about that.
Bottom line: unless you have the skill and equipment to do this installation, I do NOT recommend it. It was a royal pain to install.