I have the CZ Pro Tek 1 from CZ Customs and want to change out the front sight to the trijicon. From what I have read, the sight height is 5.5m. I know I have to tap out the drive pin with a 2mm Sight punch to remove the old sight, but why do I need to drill anything if I am going back with this sight and a new drive pin for that same gun? I don't have a drill press so I don't want to make a mistake. Any sight changers out there can answer this? Thanks.