However, each plant's CD's will have slightly different characteristics - maybe an extra barcode in the centre or different numbers. The best way to tell is by looking for the IFPI number which is usually stamped on the discs somewhere. This will tell you the exact plant that pressed the discs.
If I had received a batch of suspect CD's, the first thing I would do is run them through an error check in Plextools.
JRP Music - Audio Mastering and Restoration.