Nope, you've had the GSM side of the phone unlocked. Rooting, which you will likely need to do in order to attempt any software change, still needs to be done.

Unlocking pertains to the radio portion of the phone, and specifically, to a GSM phone. CDMA phones don't get unlocked, but the GSM portion of the phone can.

Rooting is an Android software term which basically opens the operating system to accept changes that normally wouldn't happen on their own, such as installing a version of the operating system the phone doesn't support (yet or ever, in some cases).