If you're upgrading a GenI with the GenII axle then you should get the trailing arms also - heavier duty and they bolt right up. Make sure you check the condition of the wheel studs before you decide to pull the axle - the ABS trigger wheel is mounted directly behind the wheel studs on at least some of the years, and replacing those studs entails taking the axle shaft to a machine shop where they have to cut off the bearing retainer and press off the bearing. You might be able to use that as a bargaining point if there are any wheel studs that would need to be replaced.

The locker pump is under the right side of the rear seat - there's a divider panel inside the cubby that comes out after removing a few 10mm bolts, the pump is attached to the back side of that panel.