You should be able to update the G5's firmware via the software - the latest upgrade I aquired was firmware 1.2 which gives better compatability with mouse mats. a lot of people on here moaned that the mouse was crap because it didnt work with Icemats & visa versa when simply an update to the firmware fixed it within a few minutes of me using the mouse lol. 
With yours been the 2007 version, you will most likely have yours with the latest firmwares installed in the mouse - worth checking though.

With yours been the 2007 version, you will most likely have yours with the latest firmwares installed in the mouse - worth checking though.