Is is it a problem if I factory reset my Unlocked iphone?

I had an iphone 4 unlocked on a Metro PCS store so it could work for that carrier problem is I want to factory reset it and I don't know if that is going to lock it or not. The lady at the store said maybe it won't be a problem but she didn't sound too sure and she was the one who unlocked it to begin with.

Depends on the method used to unlock it.