Some time after 911, OBL did aknowlege his involvement on at least one of his tapes. But you are rite, no one jumped on it real fast like a lot of terrorist groups do.
Yaelle, after the OKC bombing, Clinton was privately jubliant that it increased his poll numbers. The biting lip, "Ron Brown" crocidile-type tears etc.
And ... no one has ever taken credit for TWA800