Even with a pretty noisy bearing you'll need a digital thermometer to measure the temperature and compare to the other hubs to see if the suspect hub was running hotter. The wheel bearings on E36s are pretty stout so they're not very heavily loaded. If you found a hub that was significantly hotter to the touch than the others, that bearing is long past being toasted.
'96 328iC "Marie"
R.I.P 14 November 2013