I received my swatch kit from Blurb. If you are spending money on making a book with Blurb it’s essential to get this kit so you can see (and feel) the difference between the papers, endpapers, and book linens they use before paying for a costly proof copy. Also to see how images reproduce on the various stocks.
Website says it can take several weeks to arrive so allow time in your schedule, my swatch kit took about 1 week to arrive. Cost £5.94 ($7.95) swatch kit contains a code to redeem this cost when you place your book order.