Dusun or old style Kampilan?

[VVV]

I just recieved this Kampilan with an unusual "hang on" to the hilt.
The hilt is more square which I have noticed is more common on the Kampilans collected in Borneo among the Dusun (Kadazan) Dayaks of Sabah.

Until I saw the pictures of the Filipino collections in Spanish museums posted on this forum I thought that was a sign of Dusun origin.
The same with this "hang on" decoration.
But one of the Kampilans at the Madrid museum has the same kind of decoration as well as several of the Spanish collected Kampilans has the square hilt form. So maybe it's just an older fashion considering that probably the Spanish collected Kampilans are older than those collected by the US?

Also in the old books the Kampilan is attributed to the Filipino Lanun/Illanuns.
So maybe there isn't a special kind of Dusun Kampilan and they all originate from the Philippines?
The Dusun lives in Sabah that always has had a close cultural connection to the south of Philippines.

Does any forumite have any info on what the "hang on" represents?
And have you found any difference between the Borneo and Filipino Kampilans?

Michael