Per my '09 tech update book the specs on all XPs for model year 09 were:
X 36.4mm
Y-X 3mm
W 258.7mm
Z 21mm
All that changed is the new Z is 20.8mm +/- 2.3mm. So basically this bulletin is to tell you how to check it and to make a slight change of 0.2mm (hardly anything) nominally in the Z.
thanks