Unlocked Tmobile using on ATT

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I have an unlocked tmobile sgs3 that has a a few tmobile apps on it. States I cant uninstall them unless a factory reset is done. Does anyone know if I do a factory reset will it put it back to tmobile. The place where i purchased it from called me a few hours later and gave me the unlock code to enter. It works fine but just want to get rid of the tmobile apps.

Thanks in advance