Leif:
I think there is an alternative explanation for
Tagumpay. It could be the name of a town. There are many towns and areas named Tagumpay in the Philippines, but the most relevant may be
a town in the province of Nueva Ecija which is also in Central Luzon and to the northeast of Pampanga.
The blade shape of your knife is what I would call a "double clip," a distinctive shape found in central and northern Luzon, and one that is seen quite commonly on Ilokano knives. The horn (?) sheath has a trilobed toe that is similar to many Ilokano leather sheaths of the early and mid-20th C.
So I think you have a Central Luzon knife of Ilokano style that could be first half or mid-20th C. The key will be the guard. If that is aluminum, then I think it is WWII vintage or a little later.
Ian