Hello Amuk,
IMHO this is a very decent kris - do you have some of the fittings lying around somewhere? Otherwise it may be worth to contact the seller.
I'd guess at a Maguindanao piece, about 100-150 years old. Its main problem seems to be the partly broken tang. If you're not hell-bent on swinging this kris around, I'd leave it as it is. (A Moro would have certainly repaired the tang to full working glory but that wouldn't make much sense from a conservation point of view.)
I propose to use repeated soaking in vinegar and elbow grease to also clean up the gangya area and tang; afterwards a thorough polishing (by hand!) seems to be in order to remove/lessen the signs of that recent "clean-up" work...
I'm sure a final etch (I prefer hot vinegar) will bring out a nice pattern - please post pics!
Regards,
Kai