After I made the post above, I checked out the eBay seller's description of the item: "I AM SELLING SEVERAL DIFFERENT ARTICLESTHAT CAME FROM THE ESTATE OF A GENTLEMAN WHO DID EXTENSIVE TRAVELING TO THE SOUTH PACIFIC, AFRICA AND OTHER COUNTRIES".
That's interesting, as if the axe really came from Africa or from the South Pacific, then that would help in the quest for the
Origin of the Kalinga Axe ...