Moro Punal?

[imas560]

Hello,
I have just received a punal.
The overall length is approx 300mm (11.8 inch).
The scabbard bands and guard look like aluminium.
The ferrul looks like brass (almost like shell casing brass).
Any help in identification would be much appreciated.
The auction read as "Original Philippine Islands Punal Fighting Knife in very fine condition as acquired after WWII by a US GI.."
many thanks