I just had this TSB done on my 03 V6 Limited. We didn't notice the rattle because we rarely drive with the rear armrest down. But, one time it was down and the cupholders inside were rattling with every little bump.
The TSB replaces the entire armrest assembly, but I think what they did is put little rubber feet on the bottom of the cupholders so that they don't rattle... I could be wrong though.