In removing and then replacing sights, I've read that you remove the sights from the left side of the gun toward the right side (as you're looking at the gun from the rear sight end toward the muzzle end).
When you replace the sights, just the opposite - you install them starting from the right side of the gun toward the left side.
Here's a link to a posting thread on CZForum where Angus and Walt confirm this method:
http://p201.ezboard.com/fczechpistols82792frm79.showMessage?topicID=264.topic
