That's indeed what I was insinuating, but also some spearheads from Borneo have this shape (not only the blowpipes)...
Also I've seen silver ferrules on spears with provenance from Borneo, and also I've seen such decoration on a wooden shaft of Borneo spears before.
But I could be mistaken ofcourse. But for me it feels like it has some Borneo features...
Is the part where the spearhead is entering the ferrule (accented yellow) as flat as the blade itself?
On the dayak lances and blowpipes I've had in the past and still have, this part was also flat as the whole tang, which is attached on the wooden shaft with braided ratan...(see examples).