Hello Charles,
one of the best badik I've seen. I have followed the auction and when I remember correct I bid also and still keep the auction pictures.
While the Bugis are mostly Muslims, and I think that it is a Bugis badik, are the Balinese until today Hindu, they coming at the end of Mataram time from Central Java to Bali. The Mataram Kingdom, 8th -10th century was temporary a Hindu Kingdom, you still can visit on Java many Hindu temple, the most known is Prambanam (
https://en.wikipedia.org/wiki/Prambanan) so is the swastika an old known symbol in the Malay world. It's maybe a relict from this time?

I've noticed this symbol already by Balinese blades but it was the first time that I see it on a Muslim blade. I want to start already a thread after the auction was closed since I was astonished as well to see such a symbol on a badik blade. But forget it and I am now happy to see you as new owner of this piece with the same question.
Like said, a beautiful badik with some questions. I hope that others can add more to this interesting piece.
Regards,
Detlef