[coolpoete]

Not a stupid question. Once the phone is SIM unlocked you can put whatever GSM card in there and it will not ask you for another code. You are actually unlocking the device itself, not the SIM card. The only way to find out if it is already SIM unlocked is to put in an active SIM card in there. I tried with my old T-Mobile inactive SIM and it didn't work. Once I got active service it worked right away.