At a time when most people still trusted the government a huge percentage of privately held gold was not turned in. My grandmother kept hers, and gave it to her grandchildren 30 years later with a warning story about evil politicians like FDR.
Now try to imagine how much LESS the voluntary cooperation with a "turn in your gold" order would be. Near zero.
Now try to imagine the police action needed to try to confiscate peoples gold by using legal police methods. Warrents issued on sworn testimony, etc. A complete non-starter.
Now try to imagine the Feds deputizing the local police to go get gold from suspected hoarders. In my limited experience the ratio of Gold Hoarders to Gun Nuts is 1:1.
Contemplate the phrase "line in the sand" and think about how you would react to news of jackboots going door-to-door.
In short, your idea that they can do it again is silly. It makes me chuckle!
I do agree it will be more about lead than gold at that time though. If you have no currency, something will substitute for barter purposes. Otherwise it's anarchy and murder. No one will watch their family starve when you have the ability to take what you need.
As far as Obama confiscating gold, I give him a month to have half and 3 months to have 90% of it. He will have his personal army of knuckle draggers to inform on you or just break your leggs to get the info. North Korea pretty much gets what they want with no back talk, I don't see America any different after about 2-3 weeks of bloodshed. They have tanks, night vision, drones and stuff we don't even know about. To pretend a .308 will defeat the finest military on earth is a bit much. 200 patriots hole up in a compound somewhere will be met with an A-10 and a couple of 500 pounders. Just watch a few film clips on Afghanistan and see what the rags have to put up with. One could almost feel pity for them as they last about 45 seconds in a battle with the US. I have to wonder how many even complete 2 missions before they are pink mist.
Needless to say your vote is the most powerful possession a citizen has. Second to our voting properly would be educating our military and police about posse comitatus.