Those stickers generally are production or quarter dates and have no bearing on compatibility. As for the difference in part numbers, they may have different settigns for accoustics between the coupe and roadster or it may be that they superseded the older part number because of a production change or a part being made by a different manufacturer.

Either will work and you may even want to look at the ones in the SLKs as they may use the same one as well and that part number is A 170 820 06 89.

Good luck