A little update on my question: The round-pommelled hilts I speak of actually do have horns depicted on them, but are folded over the head to make the pommel round, if that makes any sense.
Here is a pic of a modern aklan taribung handle with straight horn made of wood
And here is a modern aklan taribung handle from the same maker with the rounded, 'folded horn' hilt made of wood. Note the horn, which begins at the monster's nose and extends past the back of its head as if 'slicked back' so to speak:
Another folded horn hilt, in Carabao horn:
From what I have gathered, this came into being when those who wielded these requested that the horn not protrude ad prominently in order for a slash or swing of the blade to be less inhibited. I am still unure of when this came to be or even if it is traditional. It could be a modern design adjustment in order to satisfy modern eskrimador needs.