Call me a cynic, but I don't believe the gold is at Fort Knox. If it was, they would have pictures, video, news media. It hasn't been seen since 1974 and no one has been allowed to check.
What I don't understand is why have Mnuchin make a statement that it's there? Unless the plan is to later say it's gone and the Rothschilds took it(which they were probably the ones who have it anyway).