NO, they won't. No Constiutional Amendment will pass that will circumvent the 2nd Amendment anytime in the near future. EVEN IF the feds thwart the 2nd and come for them anyway, there are MANY firearms that were manufactured and sold before registration was required in 1986. I have a couple of these, and will register them if required. BUT, even if those are taken, not all owners will be as forthcoming, and firearms will be 'coming out of the woodwork' for 50 years from non-registered private collections.
But you aren't taking them without a fight, and probably a shooting war. If that's what you big city liberals are after, it's coming closer every way with Americans who will not live under tyranny. I'm against war, but many are not.