Look in the 4wd hardware catalog or Quadratec, they would list it in the Dana 44 axle section. I'm pretty sure it was available. Mine did not have it though [img]/wwwthreads_images/icons/frown.gif[/img].
If your clutch packs aren't trashed there is an easy way. Jack up both sides of the rear and spin one tire by hand with the trans in neutral. If the other tire turns the same direction, you have the trac-loc. If it spins the other direction, you have an open diff. Also, look for a tag that says something about adding a friction modifier or additive to the diff fluid.
My Dana 44 from an '86 CJ7 does not have a trac lock. I opened the rear diff cover & looked. The trac-loc housing is more squared off & more enclosed. The open has openings on each side. FYI mine had 2.72 gears also YUK! If you have a 4wd hardware catalog, it is on page 126. #12 is the Trac-lock (open on 1 side), #17 is the standard (open on both sides & less squared). Good luck.