The label can generally be found on the back of the screen. The part number "13N7151" is highlighted in the picture below. Field replaceable unit number (FRU#) is usually an alias for the part number so if you search by FRU# you will still be able to find it under IBM Lenovo section of our website. Please make sure not to include "P/N" or "FRU" in the search box. Just search for 13N7151.
Please click on image to see actual size.