Not saying he was or was not lying. But if it was me, and if I know I'm lying, I'd go all out and say; yeah the "company men" fixed that playoff game because they took bribes and they placed bet on that game!!
Then you probably are just not a very good liar.
(but hey, a good thing right?)
Trust me when I say this with a certain amount of professional aplomb: the key to a good lie is never leaving anything out there you can get tripped up on. Or at least one of the keys (another is build the lie out of stuff you already know/have experienced so you can slip in realism + details). If Donaghy was lying, the LAST thing he would want to do is to get too specific. Because at some point that can be disproven. But now, keep it vague, play upon the prejudices that game already has attached to it, adn you can say very little and jsut let people run wild wiht by themselves. Everybody is already primed to believe. And hopefully for you they do. But if they do not and call you onit, you can just go back and point to your vague statements and say "see? I didn't say that/lie to you."
As an aside, you can see the difference between what he said about Game 6, and what he said about the Houston/Dallas series the Rockets fan keeps mentioning. In the Houston/Dallas series, Donaghy not only makes specific allegations about where the directions came from, and why, but he also gives a plausible reason why/how he would know this: he was the alternate referee for the game and so received the insturctions himself. Now there is some question whether there is anything really untoward about what the NBA did there -- contacted the refs to tell them to watch out for a call they thought they were missing. But the details provided make that one seem likely to have occurred.
The Game 6 allegation on the other hand doesn't state much of anything that everybody doesn;t already know other than that tow fo the officals wer allegedly "company men" (and actually that has been part of the popular conception fo the game too). Doesn;t mention details about how/why the directin came down, or from whom. Does not mention how Donaghy would have found out. And so...you just don't know unless he has got something concrete.