Stephen, my intent is not to make you worry more, but I recommend you play one of those CDs yourself ASAP. Also inspect any printed material to make sure it has been printed correctly. If there is anything wrong with the CD, it's better to discover it sooner rather than later.

My wife went through something similar when her CD was made. The manufacturer had the CDs all ready for pickup (they were right in our town) when she discovered that the printed paper insert had been printed wrong. It was supposed to be printed on both sides, but they only printed one side. The CDs looked OK from the outside. The manufacturer took them back and had them all unwrapped and had reprinted inserts re-inserted. It must have been a big money-loser for the company. While the manufacturing process is probably all automated, the un-assembly is probably done by hand. The reassembly was done just in time for the CD release concert, for which announcements and invitations had already been sent out.

Having worked in a manufacturing company myself, I know that small customers, people who order stuff in small batches, are often screwed over. Not intentionally, exactly, but the company will neglect the small customer in favor of devoting its resources to the big customer whose work might be in process at the same time. This means the workers who work on your project won't be as closely supervised, their work won't be as closely inspected, they won't be as careful about meeting your deadlines, etc. If they screw up, they will probably make good on their promises eventually, but they may not meet your deadline.