If your pressing doesn't have a good sample size of hashes to compare to then you use a more secure ripping method that generally makes use of the accurate stream feature (most drives manufactured in the last decade or so have it) it's a slower but more repeatable process of reading a red book CD intended to suppress jitter and alignment errors. If you get through an accurate stream rip and you encounter no read/C2 errors you're probably ok, but if you really have no/few samples to compare against you may be paranoid and rerip the disk a few times to make sure you get repeatable results or even rip the disk with another drive all together.