Just wanted to give some info on milling these guns for red dots in case it crossed anyone's mind.
We milled a customers K100 today for a Fastfire III. We assumed it would be a piece of cake as we've done quite a few CZ'S and the Grand Power seemed similar to the CZ platform.
We were WRONG. The customer wanted us to mill out the rear dovetail in the process of milling for the FF III. No problem...until we got the slide in hand and saw that that wasn't going to be possible as Grand Power conveniently milled the FPB recess exactly where one of the mounting holes would fall out. Problem number two was that in order to get any sort of depth at all with the red dot, we were going to mill into the FPB recess. The only option was to now use the bottom of the FF III as the point where the FPB spring would rest against. I called the customer and explained the situation. He agreed that moving the sight in front of the rear dovetail was about the only option we had, along with using the FF III bottom as the FPB stop. We milled just deep enough that the bottom of the FF III was at the same depth as where the OEM FPB hole would have been, so as not to sacrifice ANY reliability as far as the guns function.

Also, you have to keep in mind that the way these guns have a huge tri-cut slide top on them, there is a gap between the bottom of the red dot and the slide on the edges. It is 100% impossible to mill deep enough down to not have that gap for two reasons. One - the FPB would no longer work - at all. Two - you would mill strait through the factory lightening slots Grand Power does in that area from the factory.

These guns do come with a bit of a challenge to mill, but we got it done! Haha

Can a Grand Power be milled for a red dot? Yes it can!