No it wouldn't - he would have nothing to gain and everything to lose by testifying to what he knows publicly without any other considerations attached. I would say there's a lot more credibility in that scenario than coming forward on the heels of a book that says "$19.95" inside the front cover.
If politicians act on principle, they can cleanse themselves of most doubt by acting without an ulterior motive. A blogging Congressman spilling beans like this would not be dismissed as you theorize.
The book isn't about Able Danger. That's just a red herring for people to avoid asking serious questions. I don't care if he has a movie and TV show coming out. I want to know who knew what and when, and who buried what and when.