It sounds like the government gave the rest of the tape to the family and then the family, in true liberal form, handed it over to Moore so he could make the most political hay from. What a way to honor your son.
I didn't read the story on Salon-it could be I guess. I'll go check it out and see if it gives any indication one way or the other.
Couldn't get past the short blurb that advertised the story. Wouldn't subscribe and couldn't get the ad to work, but I think there is probably something to what you say.