Yup. Just get it on the roof and center it. Hold it in place either with a second person or masking tape. The 2 center/lower holes should be about 1/4" above the windshield molding(any less and you risk the screw not biting anything and the visor will face "DOWN", any more and the visor will face "UP".
DO yourself a favor and look a the truck with visor at all angles BEFORE drilling holes. This way you can fine tune before it is too late.
Also, replace the original LUND screws with some of the same ones, but in stainless. I put a big dab of silicone on each hole in the roof, then set the visor in place. The coat the threads of each screw w silicone and thread them in. Tight is tight, too tight is stripped. I have yet yo have one leak is 20 years