I have a couple NOS RH sun visors for AD's they are Phillips screws.
https://www.flickr.com/photos/advance-design_parts_co/12258396864/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/24630422886/in/album-72157631868452754/
As you can see on the install instructions for the GMC visor (on a box flap), it calls out the self-tapping screws.