I would think that would be way to heavy and uncomfortable to use as a headress as a whole but maybe if it was just the top of skull with the horns.
But I would lean more towards it being made to fit on the top of a post or stake as decoration or ceremonial.
I'm not very familiar with a buffalo skull but a cows skull would probably sit on a post much better if it were drilled like you are describing, because of all the bones on the bottom of the skull.