I have a 2000 model year Chev Express van, 2500 series, 8,600 GVWR, and I'm
told that it would have either a 9.5" ring gear or a 10.5" ring gear.  I'm
told the 9.5" is semi-floating with c-clips to hold in the axles and the
10.5" is full floating with a nut on the outer hub to hold in the axles.

I've looked at my hubs and I see about a 4" diameter concave dish section
with two inward facing ears.  Could be a nut, but I suspect not.  Can I be
fairly certain that I have a 9.5" differential?

Thanks, brian