Yes OE it is a clutch type & the odds are extremely great that it still is & ain't been switched & as soon as you see it you will know (cone has the visible springs/open has the visible mini spider gears) & the clutch type will pretty much be enclosed (cant see inside) & have some bolts where the case halves are bolted together. As said unless it has blued gears or chipped teeth or obvious highly worn teeth plus how tight the clutches still are it comes down to the integrity of the seller and a high ratio 2.94/2.76.3.23 out of a daily driver has a good chance of still being tight (clutches) & ok on the teeth (might be rare for the teeth to be worn badly, not sure on that,others will clarify) & the clutches can be rebuilt & Dr Diff I'm sure has the 2 buttons/pin to go in there so you can use regular bearinged axles. a 4:10/4:56 has a much greater chance of being haveing been hotrodded & needing rebuilding. I'd want a guarantee that they wont howl!
#1 #1 has HE ACTUALLY personally run it in HIS vehicle??? EDIT I reread & since it has been run with green bearinged axles that tells me that it has been hot rodded, to what extent I do not know.