Rago Fabrication KC HiLite Cyclone Rock Light Mount Install Question

I bought these brackets from Rago Fabrication and they say no drilling required, bolt right to frame, but I'm wondering where this/these locations are. Anyone with experience in seeing where these would install? I've done a bit of self installing with my truck but these kinda have me stumped.

 

It looks like the light would bolt up to the round portion of the mount. The other holes would be mounted to existing holes in the frame. I do not think they are made for a specific hole, just options so they can be mounted where you would like.

 

Yeah, there are plenty of existing holes...which would be fine if the frame was a C channel but it's not. Or if there exposed nuts/threads, but there isn't. Looks like you have to install threaded rivet nut inserts.