In a business today and saw this huge and obviously very old knife. Asked the owner about it and it had quite a history. It was made in the US (you can see the US mark and a number if you expand the first photo) and sold to a variety of countries. It is super thick and heavy. It is sharpened only on one side but its not an angled cut. It is rounded. And the edge goes all the way around the curved end. It also has a proof mark on the back.
He told me his Dad captured it in the battle of Peleliu along with some other goodies. I thought that was a coincidence as I was aboard the USS PELELIU at one point.
Sorry in advance for the photography.