Hi Tim,
Perhaps. Here's what we know:
1) the bill belongs to "[a] large sawfish [that] is distributed through much of the Indo-West Pacific region. It is, like all other Pristids, disproportionately subject to continued capture in the net gear widely employed throughout its range... It [lives] in shallow inshore coastal waters, estuaries and possibly the lower reaches of rivers. " (from the IUCN redbook page cited above). Checking
another web page , this fish can occur from the Red Sea to southern Japan. It occurs in the Torres Strait, but we certainly can't exclude quite a few other locations.
2) both of us think that the blade is around 100 years old, although I really don't know how fast sawfish bills age.
3) It has a carved hilt that could be European, could be Massim, could be whatever. I'm arguing specifically on that swelled grip, which to my thinking is more common in European (esp German) knives than on Massim clubs (don't forget that the Germans and Dutch were the original colonizers of New Guinea).
4) It's undecorated, aside from the tar/plant sap/lacquer/whatever on the hilt, and it doesn't have a wrist cord.
5) What I've been able to find out about the history of the Torres Islands suggests that, if we've got the age right, it probably wasn't made for indigenous warfare or ritual, since neither were going on in the Torres Islands 100 years ago.
It's certainly fun to argue about, but we need more evidence to settle this one way or the other.
Fearn