Before you go online to unlock your BlackBerry, it's best to check that your phone is in fact locked.
Although seeing whether a SIM card works or not is the normal way, the most accurate way is to:
Go to Menu > Options > Device > Advanced System Settings > SIM Card
Type MEPD
See if one of the lock types on the list that appears is Active.
If one or more is active, then you do need to order
BlackBerry unlock codes.