There is a box recessed into the stone behind the TV with a conduit down to the media cabinet that you see to the left of the fireplace. That is where the cables route to for connectivity. The TV itself mounts with a steel bracket right on the face of the stone but be sure it is securely bolted through to the framing lumber behind.

Ok. So the stone was even enough to just attach the mounting bracket? I was thinking of using bushings and recessing them into the stone so they sat against the backer board and extended just enough to be further out then then furthest protrusion of stone, creating four points that were on the same plane to bolt the bracket through to the framing behind.