you could apply insulation in between the studs in the walls. or you could hang that 4 x 8 compressed insulation sheets directly over the studs and then hang the rock on this once you marked your stud locations.
Personally, I would hang insulations in between the wall studs and be done with it.
Since this wall is only for partition purposes, are you going 16 OC or 24 OC? Be sure and get the proper width insulation batts so that you only have to cut lengths.