Lonnie,
You refer to a kick panel (I am assuming it must be near or under the mirror bolt holes). Is this a removable item or are you referring the sheet metal that runs on the inside side cowl from below the ledge to the floor? (sorry but I am not good on terminology)
The Factory Assembly Manual only shows one of the two attachment bolts for the mirror arm.
Here are some very poor photos of the holes in the reinforment plates. Sorry about the quality being bad - my cabs are in unheated and unlit garages for the winter (and it is also very cold out there).
The holes for the mirror are through factory holes in the reinforcement plate on each side. If you look at the passenger side plate, you'll see that the holes in the plate and the undrilled top/outside sheet metal. The locations of the two holes provide plenty of space for washers and nuts.
5/16" screws/bolts will fit easily in the holes. 5/16" hardware is what is shown in the diagram in the Factory Assembly Manual.
