I do a BOM at my LQS almost every year. Find it's a good skill builder regardless of how much sewing experience I have. I'm also a dedicated pre-washer. All that said, a with BOM when I'm getting cut pieces to sub-cut, I don't prewash. Especially if it's high quality fabrics. They typically don't run (unless it's a batik and then it's a crapshoot) and the shrinkage is generally minimal. Plus I like the 'crinkled' look after washing after being quilting. You are a better woman than me - I wouldn't have bothered. But good on you to finish up a friend's project.