It is possible to physically install the rear locker, but it is very impractical to integrate it with the vehicle electrical system. A new main wiring harness is required along with a new locker ECU and a probably a new main ECU or at least new software.
The rear locker is a stepper motor style controlled locking mechanism allowing varying degrees of lock. It is not a true "lock/NoLock" like an ARB or such.
The only practical way to retrofit is to install the rear locker and then make your own electrical control for it. I looked at the schematics and it seems straight forward for any techie type. It would be manual control and not at all as versatile as the factory fitted version.
I may try it if I could find a used rear locker to experiment on. New ones are almost 2k and that is a little steep for an experiment like this.
Gary