So in this battery the code says that is was made in S. Korea in the 4th week of December 2017.
But what does the number 3 means?
Maybe can check the codes underneath the pink wrapper (they should still be a bit visible when looking closely), then refer to this thread on how to decode them:
It’s the revision number of this model of cell, same as 2, 5 or 6 on Samsung INR18650-25R.
That code says production date is Monday December 04 2017. First week in Dec.
Thanks guys.
The last digit of the code (the 4 digits code) refers to week. Therefore its value is 1-5 (1st, 2nd, 3rd, 4th, 5th week of the month).