The 8300 has no GPS.
The 8320 has no GPS
The 8310 does have GPS.
None of these are available on Verizon. The Verizon BB's don't allow use of the GPS to any other application except their Verizon Navigator software.
If you are lost and you have cell coverage, then yes, the GPS and cell triangulation could be used to locate you. There is also a 3rd party application for the BB that lets your GPS location be sent to a server where you can allow others to track your location.