Manufacturing date is stamped inside the provided warranty card, there is no date written over the battery.
The number you are referring to is basically a serial no. of the battery, all you have to just confirm that serial nos. written both on the battery and the one inside the warranty card matches with each other. As this will ensure that the warranty card belongs to the same battery and the seller didn't cheated on you.
Always try to buy a battery with a fresh manufacturing date.