Is my father's widow entitled to a $6000.00 peice of equipment that was purchased for his business?

My father owned his own business for over 40 years. He passed away in April 2016. He made a will in 2012 that left his entire estate to my sister and me. My father remarried in April 2013. His wife signed a premarital agreement that said she had no claim to anything he owned before the marriage, but there was an exception to property acquired after the marriage. One month after they married he purchased a $6000.00 piece of equipment for his business with the business bank account that had his name and my sister's name only on it. Also during his marriage he paid his wife from that account for work she did when she helped him in his business. Does she have a legal claim to this piece of equipment?