ruby -e 'File.open("/Applications/Microsoft Office \
2004/Microsoft Entourage/rsrc") { |f| puts f.read.scan(/<key>\
CFBundleVersion<\/key>\s*<string>([^\r\t\n]*)<\/string>/) }'
It's trivial to write a similar perl one liner; I just don't write perl code unless I have to. python would be fairly simple as well, it's just harder to make it a cool one-liner.
I've only tested this with Office 11.2.x, so it might not work with older versions of Office 2004. I've altered the ruby on all my machines here, but this doesn't rely upon anything strange, so it should work with the default ruby in 10.3/10.4. It is also reliant upon the path, so if you've changed the Office folder name or location, or the name of the Entourage executable, you'll have to alter the path in the command.
Inside the Entourage Resource fork is a plst resource, which appears to be a normal plist file stuffed into a resource fork. I pull the normal CFBundleString from there. The resource fork of any file can be read with standard unix tools by reading /rsrc. The resource fork of somefile would thus be somefile/rsrc.
To figure out what I needed to read, I just ran DeRez from the Developer Tools to see what was in Entourage's resource fork.

