Mystery Old Style Central Sulawesi Penai(?)

[VVV]

This was a mystery sword for me, as well as the seller, when I bought it but now I think I feel quite sure that it comes from Sulawesi.
I am not 100% sure because the Sulawesi swords also are found in f.i. Seram and Halmahera in the Moluccas.
But the original style of the sword I think is from Central Sulawesi.
The sword obviously looks old (late 18th or early 19th C?) so maybe that's a reason why it's not often seen?

It's been a fun research project because this old style blade isn't found in the regular reference works like van Zonneveld, Stone etc.

Why Sulawesi?

- Scabbard; the only source where I have found a resembling scabbard is in the attached picture from Grubauer's Unter Kopfjägern in Central Celebes.

- Blade; the blade could be found in several places but mostly in Sulawesi.
The markings on the back of the blade is also found on other Sulawesi blades.

- Hilt; The first clue I got in the old works of Adriani-Kruyt. But most important was the picture I found in my fellow Swede Kaudern's works.
The "crocodile" hilt seems to be the old style of the Penai in Central Sulawesi. Also the pierced carvings are found on older Sulawesi swords.

I have one source I haven't been able to check yet and that's the Humaranga mentioned in Platenkamp (source van Zonneveld). Unfortunately no picture but I have seen more recent versions and they aren't that close to my sword.

Do you think I am on the right track?

Michael