Messrs. David, spunjer, AG Maisey, and kai, many thanks for your comments!
Thanks most especially to Alan for the exhaustive commentary covering the various aspects of the discussion at hand. Coincidentally, I was reviewing the other day Alan's article on the
origin of the keris.
Dr. Dizon also saw this thread by the way. And he mentioned that we should also consider the situation at the time -- i.e., that ancient Filipinos, Indonesians, and Malaysians were all maritime people, and there was really no distinct boundaries amongst them. Being genetically and culturally close relatives, he added that these peoples freely shared metal technologies among them.
On the subject kris, I also noticed that it was described that it appears that the blade's edge has more carbon content. Am mentioning this for whatever it is worth.
Lorenz