for sure it can. GEO location is being determined based on the URL, not on the actual IP of either request issuer (child proxy) or destination (parent proxy). It is about the ultimate target (host the URL is located on).
How to find the GEO location and get the block codes?
On TS, you search for the domain and the IPS
Then you cklick on an IP and see where is located:
Then you compare the country against against: http://www.iso.org/iso/english_country_names_and_code_elements
Et voila, you have the GEO location code.
One thing I forgot - Geo Location is only available for cloud data - so it won't be available in the local DB.