I purchased a new Mopar rear shock CH 68312639AB from RockAuto for my 2018 Limited (touring suspension, 18" tires), and this number was on the unopened box in multiple places. On the shock itself there's a different number P68238021AD, suspiciously close to the correct number, but not an exact match. Google lookup finds no match for the number on the shock. And the number on the shock on the car right now is again different (ends in AH, not even sure both sides are the same).

What's up with all these different numbers? I was worried I received the wrong shock from RockAuto, but now I think all the numbers except the one on the box are internal to Mopar and are not relevant.