Resolved Question: Last will and testament?

My father past away a few months ago and left a will leaving my brother and I as the inheritors. We have a long lost sister who believes she has a right to 1/3 of our estate…however the will specifically excludes her from anything. She wrote us making a fuss and saying that it can be contested? Is this true? She was excluded in bold lettering. Our probate lawyer says that chances are the courts will most definitely honor the will. I really hope so!!
The will was written 5 years ago and are father died while being in perfect mental and health conditions
Ok, in short, is she likely to win?