The serial number label for modular component tops and backs is placed on the underside of the top. The label is usually placed on the underside, center of the top.
If you have difficulty locating the label, you may need to move any of the mobile furnishings out from under the unit. Additionally, if a center drawer or keyboard tray has been installed the label may be located under these. Extend the drawer or remove the mounting plate to access the serial number label.