for my own opinon i think the meaning of what you trying to ask is a kind person whose hard headed. cowboy...

Never heard of this one. However, interesting fact! The only animal born with horns is a giraffe, others develop them when they grow. So on the other hand, when applied to a person, it could also mean someone unique, unusual, one of a king. It's just a thought tho.... :)

you may be right to your interpretation but in fact, I really haven't heard this kind of idiom (if it really is an idiom). we all know the fact that there are some mammals born with horns. maybe the one being described as "born with horns" are those characterized by animal-like behaviour or yeah, a vicious kind of person. :)