For checking on which firmware you are currently on, you will have to go to the Settings > About Phone > Firmware Version where you will find the version of Android OS where it will show 2.3.4. As you can see above that we have shown some of the images of latest Gingerbread update.
Note : You will have to reconfigure the APN settings after updating the firmware to access the data services and the Internet services as all the Internet APN settings will be reset. You will have to contact your Service provider which is Verizon Wireless to get more info on the APN Settings. Not to forget also configure the MMS Settings.
Do, let us know if you come across any issues or problems as we will see to it that all the issues are resolved.