I can believe the US government is that stupid. They probably between all agencies involved most of the answers to their questions but not enough sense or due to paranoia to put 2+2 together.
Then again the last 30 years have shown the US government is capable of anything and incompetent at everything…
There are some hilarious stories of CIA Directors and even Presidents trying to figure out what is going on and being told “you have no need to know”.
As far as I can tell the Atomic Energy Commission never briefed anybody else—ever.
For all I know they still have a craft buried in some musty basement somewhere.