The Muster Rolls are crew lists of enlisted men only upon doing further research. So with him being an Officer, he will not be in that database. I looked at my dad's records and he was an officer and his service number was typed the same and 7 digit. I requested my father's full Navy service record including medical. Before every change of duty station and rate/rank he was given a physical to clear him for that duty station. Now I did this back before the new Federal HIPPA Law so I don't know if they have that option to ask for. Glad to help.