It's a security update. That's not going to update the app to a Universal Binary.
Unfortunately, the Microsoft Office applications are - even in 2006 - CFM apps. That means that they'll need to be converted to Mach-O in order to be made UB. It also means that the current versions were probably built using CodeWarrior, so that'll all have to move over to Xcode as well. It'll be a big job to make those apps universal, and I guarantee MS will charge you for it.