I see what you're talking about, and I am 99.99% sure that there was nothing like that on the bottles that I had. I meticulously looked for anything and everything that looked like some sort of code and posted all that I could find. Judging by the way it's printed in your example, I'm certain that I would have noticed it if it were there. I regret taking more pictures now. Regardless, I guess that just serves as another good reason for returning the product.
Originally Posted By: wkcars
Found a picture on google of the back of a m1 10w-40 hm bottle, the production code it's printed in the space just above the "Questions or comments about Mobil 1?", just to the top left of the hand with the globe in it. Usually look like it was printed by a dot matrix printer. I agree better safe returning it and get something else, there's plenty of other great oils out there.