Need to take unlocked/jailbroken 2g phone back to Apple

[cleung]

I have an unlocked/jailbroken 2G phone and am a legitimate AT&T customer. I understand that in order to disguise the fact that the phone has been unlocked, I just need to go back to iTunes and "restore" it. The problem with my phone is that certain areas of my screen doesn't work. I understand from other posts that Apple has given others new refurbished phones for those affected by the screen problem. If the phone I get back has the latest firmware, can I still just use the Pwnage tool to unlock it? After reading through so many threads, I think the tool doesn't yet work for firmware 2.0.2. If so, how do I downgrade to 2.0.1? I spend most of the year living overseas so I will need the phone to be unlocked. Thanks.