SEUS Updated to CID 53, Can i unlock with IMEI?

[littlej]

Sad story.
I have a new AT&T W580i (CID52), unlocked successfully with SEtool2.
One day, i updated with sony ericsson update service (SEUS), and my phone became CID53 locked to AT&T.

Now, can I unlock the phone using IMEI unlock code, which can be purchased from ebay?
I think they access the AT&T database and find the unlock code according to the IMEI.

Thanks.