Hi JB,
Not sure if this will help, however when I installed a rearview camera in my van, I had the rear doors apart. I haven't seen any added wiring for rear speakers from the factory. Nissan uses that same head unit for a variety of vehicles. I am sure if you had the correct radio harness that allows for rear speakers, you could run your own wiring. At this point, I haven't torn into the dash yet!
Not sure if this will help, however when I installed a rearview camera in my van, I had the rear doors apart. I haven't seen any added wiring for rear speakers from the factory. Nissan uses that same head unit for a variety of vehicles. I am sure if you had the correct radio harness that allows for rear speakers, you could run your own wiring. At this point, I haven't torn into the dash yet!