Ok, I did a bit of research to refresh my memory since it has been a while since this SB was issued.
At the time the SB was issued, it seemed that all pump assemblies (the complete box) had pumps inside with the same serial # as was on the outside of the box.
It seems that when Rotax built the boxes, they etched serials #'s on the 3rd part pumps and the outside of the box, that were all the same.
So if the serial #'s on your pumps, do not match the effected range of the assembly serial #'s, then you are good to go.