Rhinoceros Horn?

I have a Vietnamese friend who has possesion of this horn he brought to the States in the 1970's. I was given to him by his Father, and is thought to be about 60 years old. He says it's a Rhino horn, although I am not sure. It is about 10" tall, is somewhat hollowed out inside. It has a wavy exterior. Most of the ones I have seen online seem to be smoother. My question is, is this a rhino horn? Any experts out there?