Well, it doesn't have the OD bearing retainer. The OD unit has a 5.125" bearing retainer. Of course, someone "could have" swapped to the small input shaft in the OD. More than likely,it's the standard 833.
Now I'm real interested to open it up and see what's in there. When I bought it, I was told it was an od and I paid OD prices.
Its my fault I didn't inspect it closer because the guy I bought it from, delivered it and set it on the shelf for me so I got lazy and didn't really look it over and took his word for it.