Wheel bearing question?

[mcbassin]

I finally got around to taking my son's 86 to get the alignment done. I put it off and then just forgot about it. Well his tires on the front are pretty worn on the inside (my stupidity). I never drive the truck so I never thought about it again. Anyway, the guy at the shop put it on the rack and jacked up the front. He checked the ball joints (pass. lower side is toast), the tie rods and wheel bearings. He said the wheel bearings are "bad" too.

On to my question. How can you tell if the wheel bearings are "bad" or just needs the spindle nut tightened a little? I had the rotors off to modify them for the boss wheels HERE. Is it possible maybe I didn't preload them properly? Is there a good way to tell if they are too worn? It's not a big deal to change them, I'm going to be changing the ball joints on the pass. side soon. The driver side looks to have been changed already and is tight.