Rear Wide Five madness! What have I got?

[Bones]

So my customer's rear wide-fives were shot so I located another pair to replace them. Set 1 came off the truck with normal wheel bearing arrangement: 3" diameter, full depth. When I opened the grease seal on set 2, the bearings were 2 3/4" diameter and a little short depth-wise before stepping up to a 3" seal (see pics). What the hell do I have and what is the right bearing for set #2? I spoke to a trusted parts supplier who informed me that in 25 years of doing this he's never heard of such a thing. Leave it to me to stump the experts! I appreciate any input from anyone with familiarity with this and thanks!