Apple Xserve (Early 2008) DIY Procedure for Logic Board - Manual (Page 19)

Xserve (Late 2006/Early 2008) Logic Board Replacement Instructions 19
Place the logic board in the box, making sure it is component-side up and positioned with 3.
the Northbridge heat sink at the back of the box.
Follow any additional return instructions for your region, and close the box. 4.
Important: Make sure the foam supports align correctly with the raised areas on the board.
When aligned correctly, the box closes easily.