Those don't really sound like they're XP updates. The issue isn't really that XP will stop checking for updated, but that updates will no longer be issued. So it's not surprising that you'd get the office updates.

However, there's also a remotely exploitable vulnerability that MS advised on recently. While they no longer report on whether XP would be vulnerable on advisories, my guess is that it's likely given the nature of things (that said, it does appear to be something that only affects machines that are on domains, so not likely an issue for people using it at home). What's interesting on this latest issue is that MS isn't releasing a fix for Windows 2003 either, even though the EOL for that isn't until this July. (Hmm, further reading and they actually include XP in the section on why they say they're not releasing a fix XP, 2003 or 2000.)