What are the odds?

My homegirl picked me up a gallon bag of Lego for my birthday a few years ago at a thrift store. Looked like star wars and I picked up the other two gallon bags from the same thrift store. I've been sorting through all my loose bricks recently and organizing them by type and today I dumped out the first thrifted bag and found a unique piece. According my research this 10x10 light grey dish with printing only exists in set 10179 aka the 2007 millennium falcon. What are the odds that I have the...