Correct, I drilled a hole and leveraged self threading bolts for the additional holes (thanks to my local Ace). But truly I don't think you need it, since ultimately they don't hold weight, they really only support impact. I suppose you could argue that the single bolt could shear off, but I think in that case the skid plate isn't deflecting impact as it's designed, something is dragging on it. One could argue in that case, you could say frame damage could result if it's on too well.
The F150 is the right one, I originally ordered the Expy and had to do several holes to get all of the panels to line up. I even re-ordered one of the pieces from them. If you ordered the entire kit with tcase etc, you may still have to drill a couple smaller holes on the very last piece. But it was easy and its strong as heck. My service tech has commented several times that it's better than most of what he sees even on raptors.