Yes to the first, no to the latter. The moisture is contained within the nug, and once that breaks up, there is more air hitting the surface area of all the bud, rather than just the outer part of the nug. However, it really doesn't matter either way.
if you grind and put it in a bag it probably doesnt matter... but dude nugz all the way i cant keep up with pre ground weed i end up smoking a quarter like its an eigth