No, that's an "official" unlock and can't be simply locked back. It should be unlocked for the life of the phone. I guess your carrier can re-lock it but highly doubt that would happen.
Plus haven't you been around long enough to know the answer to that question?
I have to make sure since I'm jailbreaking someone else's iPhone 5 for them
Jailbreak won't relock the phone, also I just replace my ip5 at the apple store and the unlock get transfer over to my replacement phone.