The tone rings were mounted on the end of the axle/1/2 shaft assy on the 07 I personally took them off of. So, yes. they were not on the housing BUT...the sensor mount was on the housing as I recall, that would be the easiest ting to solve. My point is, if you don't figure a way to mount a sensor/tone ring on the rear axle somehow (assuming you are not moving the newer rear assembly over) you are going to have problems. Maybe they have built something into the newer units, yours is 4 years newer than my donor.
It would make the swap real easy if the sensor was mounted on the transmission somehow as that is exactly what the PCS controller does.