I just had the bottom off my toughbook to add an internal logitech unifying mouse receiver and decided to replace the screws as the heads were getting worn out (I have cheap screwdrivers and poor screw removing technique). I decided to go with hex heads (allen wrench) instead of philips, but torx would have also been a good choice. The screws are M2.5x4mm with 0.45 thread pitch (which is standard for a M2.5 screw). Hopefully this helps if you want to replace a worn or missing screw....
Toughbook CF-30 Replacement Screws
Toughbook CF-30 Replacement Screws