Hopefully the filler is a tube that sticks down into the bottle and has a little "pin looking thing" sticking out of the bottom that acts as a auto-shutoff when pulled from the bottom of the bottle.
I suggest you pick up a couple hose clamps as reassurance, but you'll probably be ok w/out.
The benefit of filling from the bottom(aside for auto-shutoff), less oxygenation. Beer stores much better when oxygenation is minimized. Then again, if you're like me, your first batch will be gone so quickly, you'll be more worried about why you didn't do 2 more batches this week than oxidized beer.
