system administration, networking

Product Key for Server 2003
TO make a long story short I have ibm xseries 226 servers that came from an office that has closed down. That office was part of a purchase by my company about a year and a half ago. So the machines were setup by another IT department. When the machines were sent to our HQ they arived with OS CD’s but do not have a sticker on the outside with product codes on them.
I need to rebuid the machines but can’t enter the product keys. I need help if anyone has any suggestions. Thanks