Yes, it is the Bangai-O for the regular DS. If you have a DS mode flashcard that is compatible with the 3DS, you wouldn't need Bangai-O for this exploit. Smealum uses Bangai-O as it is his only way to run DS-mode code on his 3DS. This exploit involves running some DS-mode code to modify the DS-mode profile of the 3DS in some way, and then you load up the DS-mode profile settings on the 3DS and the exploit happens.
But as has already been said, this exploit is not being released right now, and may not be released at all. There is no point in releasing it at the moment. So don't worry about buying things in preparation for it. Besides, you should be able to find a DS-mode, 3DS compatible flashcard for about $5.
On the other hand, Bangai-O is a nice little game, and IMO well worth $5.