Welcome to the active members guild of the forum!
Yes, IMHO there is a good possibility that this may be from one of the Lumad peoples: The non-traditional hilt, work at the gangya area, as well as the flat tang tapering into a longish round tip doesn't look like traditional Moro work. OTOH, I guess that a sound cleaning, polishing and etching will reveal this to lack a seperate gangya and from the craftmanship I believe this blade is post-WW2 which would also allow for other non-traditional origins. (I'm pretty sure this isn't an early blade.)
There's still a chance that the blade is laminated and I'd suggest to check it out. Please give it a try and post some more pics!
Regards,
Kai