[Brad54]

Don't walk away from it yet: If it's an auto, but it has locking hubs, it could be a posi. I don't know if manually locking hubs were an option of automatci-equipped trucks: I just know that every time I've run across an automatic 4x4 in the junkyard from that era--be it Chevy or Dodge-- they all have fixed hubs with no manual locks.

It's very possible someone might have added locking hubs to that truck, and then added a posi-unit, too. Ask for pics of the hubs, and when you get there pull the cover to see if it's a posi unit. (or just spin one tire and hold the other, with the hubs engaged. If they both spin, it's posi, if you can stop one, it's not)

-Brad
(on a side note, I enjoy every post you've made about your truck!)