There are two (three) opposing points of view.
I. Heller protects all firearms in common use for lawful purposes (generally speaking, most of the guns - minus NFA weapons - for sale throughout the US at the time the decision was published). In this interpretation, if a firearm is in common circulation, then it is protected in its current form.
II. Heller extends protection to "firearms" and not "accessories". In this interpretation, AWBs do not violate Heller because they restrict ownership of "accessories" (features) of guns and not the guns themselves. (This is entirely refutable based upon the reversibility clause in most modern AWB proposals.)
(III. Heller is an illegitimate reading of the second amendment and should be overruled accordingly. I write this in parenthesis because it is a general opinion most gun control advocates hold about Heller and not an actual interpretation of the Court's opinion.)