Hmm. Let me see if I can work this one through... I presume the reason NASA is so desperately afraid to get their "faked" moon dust back is because it might fall into the hands of independent geologists who might conclude that it didn't really came from the moon.
Yet NASA is completely untroubled that over the past 40 years they've already given much larger amounts of Apollo lunar material to those same independent geologists all over the world, all of whom have pronounced it genuine. They've also placed samples on display in various worldwide museums where, although they cannot be easily subjected to laboratory tests, can at least be examined and even touched by any interested member of the public, including any geologists who might have been able to get their own samples direct from NASA.
Sure, why not. Makes as much sense as any other hoax conspiracy theory!