You don't have to use exactly same FRU # as you have
Go to IBM web site for detail and get T40,T41,T42 bios update
(same update file for all three model).
Link for Bios update :
http://www-307.ibm.com/pc/support/site.wss/document.do?sitestyle=lenovo&lndocid=MIGR-50275
Let us know if you have more question.
IBM