If you look at the parts diagrams posted (Thanks MiniJeepTV, I was only ablle to see thumbnails previously), the bumper fasci has no hole. There is a bezel for the trailer hitch. The bezel has to be put in the fascia. While the mopar hitch can be bought, and the bezel can be bought, there appears to be no special fascia with a factory hole in it.
This means either 1) the fascia to fit the bezel is only a factory part and not orderable. or 2) the factory uses the normal fascia, but has a machine to punch out the holes consistently (or moral equivalent)
In either of these cases, it means for a dealer to add it, they have to make the hole. That hole has to be the right size for the toy tabs to anchor the bezel in the hole without it falling out or vibrating a lot. The toy tabs probably leave them about 1/2" or less of variance to achieve that.
In the case of the launch of the 2011 GC, there was either a shortage, or absence of trailer hitch equipped vehicles. The solution for some dealers to this was to tell buyers it was a dealer installed option, buy the bezel/garnish, then to send bubba the shop money out to the lot with a sawzall to cut a hole in the back of several people's $40-60k car that was less than 30 days old. Bubba the shop monkey and a sawzall are not precision instruments, especially when their goal was to bang out the install in less than an hour. Add to the lack of precision that bubba maybe didn't graduate top of his geometry class back in high school, and asking him to measure to within a small margin of error a particular location on a malleable object with curvy bits on the end rather than sharp straight corners.
It went something like measure once, cut twice, uh oh, measure twice, cut three times, that holes too big and in the wrong place we'll just rest things in there and hope the owner doesn't notice the gap and it doesn't fall out. What do you mean it's not centered?
One of the other ones was at least more fixable in that they just cut a small square hole and didn't expose the wiring harness socket. So they at least stuck to the "you can always cut more off, you can't put the stuff back later" ethos.