In my near/never ending bearing search through the internet, I finally found a few matched for my rear bearing numbers. Unfortunately, the roller bearings are out of stock everywhere I look, so I'm back to looking at a few specialized volvo parts suppliers Skandix and SwedishTreasures.

Both show two types of rear wheel bearing for 122s. ENV and Spicer. ENV is listed as "very rare" while spicers are listed as more common.

I've no idea what the difference between these two are, but the pictures at the Skandix site betray no difference between the two types and provide no bearing numbers.

When I asked at the carquest parts store, they only had a single number for all rear bearings for 544s 122s and 1800s. So how different can the bearings themselves be?