Mike, If your outer seals aren't leaking, wash out the dirty grease, inspect the bearings for pits or rust. If they look good, repack them. Replace your inner seals, then put them back in and set the end play.
No sense in changing out good bearings unless you have to get to the outer seals.
Inner seals are easy to change and so are the foam gaskets so that is as far as I'd go for normal maintenace if the bearings look good. Just regrease them with a good Ford-spec MOLY front wheel bearing grease.