I have constructed mount holes in many ways, pads on all layers of the board, pads on just on top and bottom and no pads at all. It really depends on the type of hardware used in the mounting hole and its application. For example, if you using a #6 or #8 screw with an external or internal tooth lock washer you may want to have a nice copper pad for it to rest on so it does not tear up the bare laminate. Also there is always concern with the compression zone around the mounting hole causing issues on inner layers and if there are pads on every layer from the mounting hole it will help strengthen the area as you indicated.Originally posted in cdnusers.org by mcatramb91
Now if this mounting holes needs to be connected to a Ground plane then I would strongly suggest using vias or pins around the mounting hole to ensure the connection to the Ground plane remains reliable, most design today use this technique and you may already. If you just use a plated thru mounting hole then you risk fracturing the hole wall and breaking the connection the Ground plane which could lead reliability problems.