Pull the tailshaft housing off this will shed some light on the roller bearing (note you have to have a different yoke for a rollerized tail housing)for sure and you may be able to tell if it's an after market tail shaft some are marked. I know the 1.82 tail shafts have a counter bore rather than a center in them, also the stock tail shaft are usually black, which means they we machined after heat treating and most after market show a brighter finish on the machining. None of this is fool proof though. Don't always trust the stampings on the end of the rtail shaft, there was an article/thread on here a few months ago where a person bought a supposedly built to the hilt transmission, and the tail shaft was stamped, when he took it apart it was totally stock, meaning somebody scammed someone by stamping #'s on the tail shaft.
JMO
Zip.