front license bracket

so how do i get the front license plate bracket off of a 94 lesabre custom?? i got two screws out from the bottom but still have two more to go but i cant figure out what they are. they dont seem to be the same size or type of screw. they are located where the top of the license would be and the only way to access them is through the back (radiator side) of the bumper. do they pop off are they hex screws are they a philips or a slot head screw??????????? aaaaargh