Possibly contesting will

My mother's will/trust states that all of the possesions in her house go to me. Brother inherits the house and child of deceased sibling receives $150,000 in cash. Child of deceased sibling states that the piano in the house belonged to her father - actually had come from great grandmother's house - and therefore she is taking her piano. 3 months before my mother's death, she had me write up what things in the house she wanted to give to her grandchildren and nieces and nephews - even though, I received the contents of the house, I want to respect my mother's wishes. The piano was given to my daughter. My brother's will never mentioned the piano but did mention specifically other property that my mother gave him that had come from my greatgrandmother's. She said today that she will fight for her piano. There is a no contest clause - is this contesting the will and what are her chances?

That is not quite contesting the will if the item was never supposed to be covered by the will.

But a judge can decide...if you all cannot agree