You'll possibly be OK, but since you're going through both the AC condenser and the radiator I wouldn't particularly recommend it. I'd suggest just using the straps they provide for mounting like I did. Still is pretty quick and it's actually held up well enough that I haven't needed to adjust or replace them yet.
I used all existing holes since I prefer to not drill the body if I can help it.
For the bottom right there is an existing hole that I put a bolt through, I fastened the bolt on first with a nut and lock washer and then slipped the bracket over it and added another nut so that I could remove it without trying to get back there each time.
More detail in my build thread:
https://www.hummer4x4offroad.com/fo...-s-Alpha-build?p=222180&viewfull=1#post222180
Be super careful to keep the hoses away from the AC condenser. I didn't the first time and ended up with one of them rubbing through a tube in the condenser while I was in Moab. That really sucked to not have AC down there. It doesn't take much to wear it thin enough to blow since it's relatively high pressure in those tubes.