No it isn't, it would be like walking into a burger king with a burger king burger asking for condiments to go but nothing to drink so you can go get your beverage of choice at a dunkin donuts which you prefer over their fountain drinks.
You aren't asking AT&T to unlock a T-Mobile phone here. It's an AT&T phone that may or may not have been on their network at some time but it is locked to their network. They can look up and see if the contract was completed OK or you can provide a receipt that it was purchased full price and they will unlock like the apple stores were (and still are??) doing.
I am pretty sure I flew in under the wire but when I did my unlock I did make sure they knew I was currently a Go Phone subscriber, they could tell by my number. Maybe someone stuck could try that angle? Or go on a monthly full AT&T service without contract term commitment? Should get you in the door past this technicality.
It is pretty nice that they are unlocking some phones but I really don't agree with that detail. I don't agree with the crap they just pulled over on the Go Phone side either so I am ditching them also. I honestly don't know why carriers need to be such dirtbags in the US.