It isn't the fact that he needs new recovery cds. Many models share the same motherboard, and each motherboard gets "tatooed" with what model the motherboard was installed into. Its a bios string. When you go to restore the system, the restore cds check for the string to be in the bios, if the string wasn't "tatooed" into the bios, the restore will not run because it thinks it is the incorrect model, being it couldn't locate the bios string information.
Many manufacturers do this, including HP, COMPAQ, Toshiba, etc. I see it all the time at work. As far as installing XP Pro, you can definately do that, HOWEVER, without that bios string, NONE of the sony software or updates on their website will work correctly, because sony updates, much like restore cds, check the bios string prior to installing, if it doesn't match, the updates will NOT install. (including the drivers posted on their website)
I would strongly reccomend contacting sony, as not only will this inhibit the system recovery and the installation of all pre-installed software (if you actually use it), none of the official sony updates posted @ sony.com/support
Unfortunately, sony will not send you the software to tatoo it yourself, it will need to be sent back in.