Hi David
Yes, you can set your Event Aggregator imports to update based upon changes made to Google Calendar. When the time comes, head to Events » Settings » Imports » Event Update Authority and select Overwrite my event with any changes from the original source.
Just a note: due to the limitations of the iCal standards, if an event is completely deleted in Google Calendar, you will need to manually delete it from your site.
Is there anything else I can help you with?
Thanks
Courtney 🙂