let me explain, standard practise is that all hardware is not allowed to leave the premesis.
all computer hardware is there for left in a really big cuboard, My friends father has "helped himslef" to a few PCs in the past, but is always very carefull about what he takes, who he lets know about it, and what happens to it.
the PC may be marked Property of US government, but aside from that there would be no way to trace it back, and certainly the hard disks would have been wipped over many many times.
Come to think of it I have US army CPU fan as extra cooling on my graphics card.