He found the hole already. I think the car never uses the carpet securing screw so the floor carpet (not the mat) covers the hole and not easily seen. You have to rub around the area to locate it. The hole is already there and the carpet is already punched, u just need to find it.
I read somewhere the original purpose of the hole is to drain any water that gets into the footwell, but then adapted to use the carpet securing screw as a double purpose.