Not sure exactly what determines an autotrac, but we're doing a 2007 4wd right now. It has the MP2303 transfer case, selectable range switch and nobody has the input gear for it.
But we have it all apart and i'm pretty sure we got the right gear coming in monday; we'll post up a how to or how it turns out.
The NP case has been done, as we know. As far as I know, this case hasn't

There were two options for this case, the 80e and 60e, the 80e has a 32spline and the 60e has the 27 spline.
The GM exploded pic shows the 32spline being an option, that's we ordered.

Can't wait to see it work!