IBM X32 - Manual (Page 125)

For X31 and X32 series
When you order a new base cover, you also need to
order the label kit. Check the FRU no. on both
FRUs first and order them at same time. Stick the
label kit on the new base cover as indicated in the
following figure.
Removing and replacing a FRU
ThinkPad X30, X31, X32 121