Gun Confiscation: Will you turn yours in rather than wait for the door kicking session.

This article says you turn them in voluntarily. 
He said it was to slap gun owners awake and good for him if he did wake a few up.

As for turn ins.  Do what makes you feel better, safer, and accept the accompanying fate.

Ammo will be the real concern since they can choke that supply off easier than guns.  Imagine a world of cars without gas.  Ammo shortages have already been implemented by the ruling class as a test most likely.

Have a few extra guns around that are way old and probably not trackable, and whatever you do make sure you have enough to feed them for an extended period of time.

I somehow agree that they probably won't go door to door initially, but rather will first keep adding groups of people who must lose their gun rights for various reasons, Veterans with PTSD, Medical Marijuana Users, Drunk Divers and then later seat belt violators, and alimony delinquents.  Eventually the list might include mental illnesses that are defined by believing in the Constitution or anyone who utters things that are not approved by the collective.

Finally, they might come after online commenters and bloggers who suggest any kind of resistance to overt actions by the government even if the resistance is only in the form of non-compliance to illegal edicts.