Just curious. I just swapped out the battery on my 2005 ML350 (first gen ML350). Since I bought the car used, I don't have a full service/maintenance history but I am pretty sure the battery was original. Aside from many printed labels which did not seem to have any date information, there was an identifier "01JFP" hand etched in the battery by one of the posts so I am pretty sure that is the date identifier and that the battery goes back to 2001! My reason is that the 0 can't be a letter O since O would not correspond to a month. The second digit, I believe, can't be a letter "i" because that is not used because of number/letter confusion. So my thinking the battery was from 2001 in the month of October (the letter "J").

If so, kudos to Mercedes! Awesome. If not, never mind.