I did ask him about that. I gather that this was a workplace rumor rather than something he was directly told. (You know, he has an email address at his blog. You could always ask him about this stuff yourself!)
You're right, somebody who was interesting in pursuing this could email him. I wouldn't expect a very straight answer from somebody claiming to know the truth of the Ngo Dinh Diem coup, though! <LOL>
Even if it was a << workplace rumor rather than something he was directly told >>, that barely matters. Let's just say that his co-workers must have been interesting fellows.
Either he has connexions, or it was a white lie and he wants us to think he has connexions.