Thanks Ron for confirming what I discovered today doing my own research: yes Col. J T Orsdale under Gen. Wood. In fact, in 1904 he led a second expedition on the Rio Grande river in Maguindanao country. Thus you are right, this is around the turn of the century.
I wasn't quite sure of the date since on the one hand it has the a mono-steel blade with sharp luks, but on the other hand it has a distinct separate ganga.
Also according to Oliver Pinchot in an email, the Jawi says, " Datu Fi'cha" (spelling of the name might be a little off). I will now look for information for this Maguindanao datu.
I also thank you David for the picture.
And yes - this does add a wrinkle to the sharp look theory.
Yes I am as pleased as punch!