I ran into this dilemma with my 5ver hitch on my 04. 5. The frame, per Dodge, is not to be welded or drilled on. So when I asked my Dealer they recommended me to a welder that would certify the welds. And the company that sold me the hitch said they would drill, to attach it.
So which is it?
I researched for a couple of months and came up with a bracket sold by Reese that is clamped to the frame. I don't know about the receiver hitch but I would research it before you do either, as I did, and find a better solution. If out of warranty, I don't think its as critical, but a certified welder willing to stand behind his work would be OK for me if out of warranty. The hydro formed frame is the reason for it being sensitive to either.