Having read through a fair amount of the messages I would surmise their authenticity by virtue of the fact that forging 573,000 pager messages, with enormous amounts of cross-referenceable information, accurate timings, including excerpts from news networks reporting via other channels, etc. would be a prohibitively difficult task.
It is plausible, of course, that the bulk of the pager messages are authentic but that the individual acting as the source could have inserted forged messages amidst these, perhaps with the intention of fanning the flames of conspiracy theories with references to bombs, explosions, etc.
However, I don't think there are grounds to dismiss the entire set of data as fake.
I hope you're not defending a LIHOP (Let It Happen On Purpose) position here?