I recently went through this. The only issue I had with buying the complete hub was that it came with chinese bearings, not the Koyo's that lasted since 1990. I found this out after purchasing the hubs, as its the only moving part i took a quick trip to Napa to buy replacement Koyo bearings and Timken race. Pricey but I hope they last another 20 ish years.
- -To answer your question about how to figure out what bearing it is... There should be a number on the outer face of the bearing. I will depend on the size of the spindle which you could measure with some calipers/ micrometer.