by Octillion » 16 Jul 2006 18:28
Those are tamper resistant screws. They are filed down on the top like that so they can be screwed in like normal, but it is difficult to remove them as there is nothing for the screwdriver to grip onto. If you simply deepen the screw notch with a Dremel or similar tool you can then unscrew it.
Since this is a double sided deadbolt, you would want these screws on both sides. If only one side had screws, someone could simply remove the screws and remove the lock. Having screws on both sides will not give someone access to do that, regardless of what side they are on.