Grip screw on mine is Allen head, takes a 3/16. I don't recall getting the wrench with mine, and I don't think the instructions cover grip removal
I've seen some of those.
First time I ever came across an allen head screw on an AR grip, let's just say their ear was probably burning for a while because I was pretty vocal about how stupid that was.
They're supposed to be a flat head screw.
Everyone has a flat head screwdriver. But not everyone has a 4 or 5 inch long allen key.