Old knife with military markings -- ideas?

[Ian]

Here are some pictures of the hilt of the knife above. The first one shows the tear drop cross section as reflected in the shape of the butt plate (the edge of the blade is oriented up in each of these pictures). The pointed end of the tear drop is quite sharp, and that sharpness is reflected in the shape of the wooden grip. A narrow ridge runs down the edge-side of the handle, as seen in the second picture -- the shadow on the back side of the handle serving to indicate the sharp demarcation of the sides of the handle around this ridge. Not your usual Philippine knife handle, and I would suggest more of a European trait than a local native feature.