I have not mounted one of these myself, but it looks like drilling is only required on guns without a dovetail rear sight. The instructions indicate that there is a base that mounts in the dovetail and the sight is mounted on the base. You just need the correct dovetail base to fit a CZ. The following is copied from Leupold's web site.
Installation
Installation on most handguns requires the use of one of the included mount bases. Leupold recommends utilizing a qualified gunsmith to press/remove the rear sight from your handgun. Once the rear sight has been removed, the appropriate dovetail replaces the rear sight, with the part number facing up. Some installations (Kimber / Smith & Wesson M&P)require the use of the included set screws to be placed in the dovetail to hold it in place and the M4 x 0.7mm Torx® screws will fasten into the dovetail plate extension.
The corresponding mount base for your pistol is placed on top of the slide and over the dovetail with the flat part number side facing up through the slot in the base. Once the dovetail and mount base have been placed on the slide, the DeltaPoint is placed on top of the base. The four holes in the bottom of the DeltaPoint will align with the four short posts on the mount base and secure into the dovetail using the two included M4 x 0.7mm Torx® screws ( Figure 1). Secure the screws by applying 20 inch pounds of torque. Securing these screws creates a press-fit and will hold the DeltaPoint firmly in place. Call Leupold customer service for details specific to your handgun. For rifle / shotgun applications, the Cross-Slot Mount allows fast and easy mounting on Weaver-style or Picatinny bases / rails.