Fort Knox is totally empty.
Back in the 80's when Ft Knox was the US Army Armor Center where all tankers and scouts were trained, there was an entire company or troop of trainees who were tasked with being the QRF for the gold vault. This was rotated every 24 hours. The troops were moved from their regular barracks to housing closer to the gold vault, all the tracks had weapons mounted and there were fully loaded ammo trucks standing in the motor pool.
When Ft Knox became the Army Personnel Center, there were no longer enough combat trained troops on post to respond to an incident at the depository. All the gold had been moved to the Fed's NYC underground vaults. I'm pretty sure everyone here knows under what buildings those vaults were located.