The VZW SIM card int he 9650 is only used on VZW when traveling abroad. If you never activated the international feature/international voice/data roaming then it's unactivated and does not have any of your personal information on it except for the SIM address book if you saved your address book information on it. If you are weary remove it as the next person who wants the feature can get a new VZW International SIM card shipped to them from VZW or pick one up at the VZW store. I highly recommend updating to the latest software and doing a master reset on it to wipe everthing on it.
The 9650 is an AWESOME multi-band world-phone device and I envy you (People I know are currently running the Storm2, the physical keyboard is a must these days versus the touch screen...).