Unless Gateway modified Windows XP to support EFI, GPT and UGA (which is extremely unlikely), this DVD is pretty much like any other computer's recovery disk.
Would a bootable install dvd for the Gateway 600 series do us any good? I'm trying to think of what properties would be changed between that and a generic install. Would the DVD just use legacy BIOS support and install regularly or would it require some extra EFI components to boot? If so, would a patched [to eradicate the error msg that says "this will only work on 600 series" ] dvd work for this? I'm really novice, i'm just throwing ideas out there.
What we would need is an image of the hidden EFI partition (first FAT-partition on the main hard drive) and a ROM dump of the EFI chip (or maybe an EFI update file). From these, someone may be able to extract the CSM module and the BIOS image.