I have a pdf file of the complete GM microfiche for the 91-96 Chevrolet B-Body parts list.
It's a truly wondrous document if you have one of these cars.
A buddy is going through tribulations with The Car Formerly Known As The Biscayne SS.
He ditched the drum brake rear end for a disc brake rear.
When he had that done he also upgraded to strange axles and a super-duper gear style locking differential.
Three years and 4k miles later things went pear shaped and one of the axle seals failed and all the fluid took the opportunity to depart containment.
When they were pulling things apart, they discovered the axle bearings were of the "axle-saver" style and not the standard type.
My buddy indicated he purchased new bearings with the new axles and gave them to his mechanic, Mike.
Mike has since stated that the bearings that my buddy provided were "loose" and he replaced them with what was found in the tube all fallen apart.
Which brings us back to the parts list!
You could get two different kinds of brakes and three different diameter ring gears in the 91-96 Caprice/Impala.
There are several housings to account for it, but there's only two axle bearings to deal with.
One is for wagons using the very common 8.50/8.625" ring gear 10-bolt and drum brakes.
The other is for all other applications.
I wonder if my buddy got a set for a wagon which is expecting larger diameter axles and that Mike didn't check and just assumed the loose was because of worn surface on the new axle.
I am watching from afar.