IF the strangeness was linked SOLELY to the bearing, then you will not need one.
if you are not sure, however, then the alignment could very well be off either way, and getting one done wouldn't hurt.
as a rule, though, you shouldn't need an alignment after simply having the bearing replaced.
(I'm TELLIN YOU!! pull it off, and have it pressed for 40-60 bucks! then take that extra 100, and buy yourself something nice!!!)
Ray
