Hello Pukka,
have bought some time ago a kris from Mindanao/Philippines by the same seller. Look here:
http://www.vikingsword.com/vb/showthread.php?t=12825
He told me that it is from his passed away father's collection.
Agree with you that gangya (fret) area is very nice elaborate. Seems to be a fighting piece with good age and prevalently used. Others with more knowledge will tell you more.
Regards,
Detlef