Question about licensed file in MS Office

[--== Alain ==--]

Hi,

In our company we have several version of MS Office installed (XP, 2003
or 2007).

Some have been bought as standard office suite, some as update of
previous version.

Now is my question :
With our auditing software we detect on the same computer 2 MS office
installed (for example : 2003 and 2007)

On which based can we tell that 2007 is an update of our 2003 version ?

it can be that this person has 2 standard licenses and not 1 standard
license + 1 upgrade license.

Is there a particular file on which we can base our software audit ?

for example on windows XP, it exists the "winver.exe" which is a clear
statement on which version is installed.

thanks a lot,

Al.