I can't answer the question absolutely, but offer this as someone who wrote a lot of software. Suites like Office share common frameworks and code to prevent the software from being even larger than they are. This common framework and/or code is stored in common files called a DLL that are referenced when a feature within them is needed. So Access AND Excel may both use ABC.dll and Word AND Access may both use XYZ.dll. Theoretically if there is a patch in abc.dll or xyz.dll that is important and they put it out there, you want it because Access is going to use it - even if it is labeled a Word update or Excel patch. Edit: This is in addition to any changes that might be done in code that is specific to Access itself - but that is always going to be marked an "Access update".
All that said, modern software building often has tremendously complex build procedures that indicate all these dependencies, and they should be extremely accurate indicating which software is affected by which changes. If it doesn't say Access is affected, then in theory you don't need it.
But you are risking your safety and workflow to a typo or an omission by whoever is managing the process, often the lowest person on the software team totem pole. That's a risk you are taking.
Edit: Tony's point is valid though - if you've got software that isn't updated on your machine (Word/Excel 2003) and in a rush you click the old icon - you've opened/accessed an unprotected piece of software. If you aren't going to update the old Word/Excel think I might uninstall the unused parts of the old suite to prevent an accidental click causing an issue.
