How to see if Office 2003 Service Pack 2 is installed remotely in AD environment
There's nothing in AD that specifically tracks the SP install level. If you were controlling application and update installs via WSUS and Software Distribution you'd have the info in one of those.
Otherwise, you're stuck determining by either Add/Remove Programs or by file version info.
From Microsoft: "How to check the version of Office 2003 products".
You could probably whip up a login script that checked the information via something like MS/Sysinternal's Sigcheck and reported it back via event logs or alike.
There's also a similar discussion over at StackOverflow which may help.