I had a problem with an IBM Thinkpad X40 not displaying it Serial Number, Machine Type and UUID. While you can ignore it when these informations are missing in the BIOS, there are other aspects. I found that the automatic software update feature does not work as well as some software products bundled with the Thinkpad as they will run on Thinkpads only.
I contacted the IBM hardware support and because of a three year onsite support contract an IBM specialist visited me to fix the problem. He had a special floppy disk with a program he used to flash the missing information into an EEPROM on the systems mainboard. Before you ask: This program is not available for download, you have to contact IBM hardware support if you face that problem too.