I don't think so. The Bali explosion hasn't been claimed by anyone yet. It's just that it's pointing in their direction or the direction of Jemaah Islamiah so far (and on another thread some are linking the explosive used to the Indonesian army). But no one has claimed it yet.
And did ObL actually claim WTC? I forget now.
I'm also amongst the people who get ticked at the talking heads who insist al Qaeda always makes a big stink out of taking credit -- ain't that Hamas? ;-)
--KL