Once a male hits puberty, man breas-ts can show up at any point of time. So, there is no one specific age range as such once a male hits puberty. It could practically show up at any age.
As far as the procedure is concerned, depending on health conditions and some specific parameters, the surgical procedure can be conducted on anyone. Some experts ask the patient, if an adolescent, to wait till they turn an adult i.e. the age of 18 years, based on their overall physical condition. It requires a scrutiny by an expert in the subject matter to determine the appropriate time for the procedure to be conducted.