Two things that usually make noise in the front end of these are wheel bearings, and side carrier bearings in the front axle. Usually the front axle only makes noise when its locked in and isn't typically left or right specific, but speed related.
Since your noise is sensitive to left/right motion, I would have to agree on your suspicion of the wheel bearing. If it gets worse on right turns, then the left bearing is suspect, as much of the vehicles weight is shifted to the left side during a right turn.
Sometimes you can jack the truck up by the frame or control arm and shake the wheel up/down. If there is noticeable play, then the bearing is no good. These sealed hubs don't have the "play" the older repackable bearings have and therefore should be tight (no movement).