A few points.
a) the United States has not been on the gold standard since 1933 and completely since 1971. In fact, there is no government currently in existence that is on the gold standard. So why should the US government of all organizations "supposed to be" on the standard to begin with?
b) gold and tungsten have a variation in mass. Basically, if you put two similar sized bars of "gold like material" next to each other, one of solid gold and one of gold plated tungsten and equated them... the gold would be heavier. The weight would exponentially increase in the varied amount of gold/gold-plated tungsten weighed. Would this mean that the people being duped (Asians in particular since they are the target of this gold scam) would not especially pay attention to this fundamental fact and weigh the product they were buying?
It's funny because in all of the conspiracy theories, no one ever really addresses the gigantic, whale sized "conspiracy" going on with the production with excess currency supply. It's on the news everyday.