If the feds come to your door, do not lie. That in itself is a crime. You must not lie to a federal officer. However, you can refuse to answer their questions, and you can refuse their entry into your home. You will have time to conceal your guns.
That said, when your guns are outlawed, you won't have much use for them except when the final chapter opens. You can't take them to the rane, you can't let anyone know you have them, you can't use them at all.
It's a tough call. When you know you are a felon by keeping what the 2nd Amendment allows you to keep, and when you know the ATF has been granted authority to ignore your rights, when you know you will go to jail if you hide and keep what is illegal, what should you do?
We are looking at a phase of what will be history that has never befallen the U.S. It's a different nation now. Obama has changed it. Eash of us need to decide in advance of legal gun seizures what we will do.