iPhone 3GS Factory Unlock?

[if10w]

I want to share my story since am sure is not all that common.
I visit Apple genius bar yestarday 8-2-2010 , and got my 3GS replace, I arrive home and removed the old AT&T sim and I insert my T-mobile sim card, just before I visit Jailbreakme.com. I got the iPhone is activated message???so guess what i got T-Mobile and full bar signal I made couple phone calls and yes working perfect. Am guessing they gave me a factory unlock iPhone 3GS. I also went to apple.com and check on the warranty, and now i have warranty till 8-25-2011. My location is Florida.

Anyone has had this happen to them??? How much does a factory unlock 3GS goes for in US?
Heres screenshot proof, and i can provide any other proof if needed. Yes jailbroke my iphone but i dint have the need to.

[Cowboy]

There going i would say about 500 or so factory unlocked. AND it seems to me you just lucked out with getting one from the apple store.