Just as the AFOL community patted themselves on their collective backs for cracking the Series 3 dot codes, it is turning out that the system isn't always reliable.
Victor wrote to let me know that even with the cheat sheet in hand, he felt the codes didn't always get the job done (the baseball player codes didn't seem to be terribly accurate). I'm posting an improved cheat sheet above (click the image for a larger view) from phamjod which originally appeared on FBTB. This adds the placement of the creases on the bag to aid identification. This sheet seems to be 'better', but you may still face challenges. I'll work to update the link in the guides, but at least you will have this for now.
This has only been confirmed for the US to date. A cheat sheet for the UK/EU has not materialized to the best of my knowledge.
With January 1st, the official launch date of Series 3, a day away, I hope this will help you find the figures you are looking for.
Remember that if you question the dots on your package, you can always try to 'feel it out' through the bag.