Having replaced at lease six hub bearing units in my last rig (Nissan Armada w/IFS & IRS) I would remove any/all surface rust/corrosion at the mating surface of the knuckles where the new hub sits, because it makes installation that much easier.
Rust/corrosion causes expansion, and you'd be surprised by how much of a nightmare it is to fit something that has a .0001" concentric ring less to work with.
Add all the anti-seize in the world, because the next guy to work on your truck is likely to be you.
FYI, buy Timken once, or the other stuff again.