I hope you don't think it really makes a difference?
All they need to do is find the right combination of words to keep stringing more people along so the SP rises and I can get the hell out. Once thing is for sure, there is NOTHING of value in those hills. Know what you own. That used to be a mantra around here with a different implied meaning.
It's possible that the NDA is still in effect. I have signed some that call for 3 to 5 years (after the termination of any deal) before they can be made public. It is unusual but not rare.
However
I do not know what the rule would be if one of the parties defaulted on the deal. Would the parties still be bound by the NDA ?