From the pic the seller posted, I can't make out for sure it's a GV unit attached to back of the T-19 trans. If it is, GV makes a front case for their unit that allows it to be mounted in place of the carrier bearing, which makes it a "divorced" GV unit. I have one. [GV divorced]
Seems to me, ideal for 4x4 application. You could run a normal transfer case at the back of the trans [thinking 5 speed even] and when you are 4x4, go direct drive on the GV. When you are on highway, out of 4x4, use GV to drive the rear wheels normal way.