Just had another quick research into the box, seems as there was an upgrade in 2001 with the C32 AMG box, the box is also called a NAG1 box and it seems that as these are used in more powerful US cars for Dodge and Chrysler there are upgraded valvebodies available.

I will see what my box is like, I will be swapping out the fluid anyway after buying a dipstick for it - will look into upgrading to an AMG box with perhaps upgraded valvebodies in the future.