Hello Glenn, the term galvanized Yankees may not have been widely known, however a clerk at Fort Delaware in 1863 used that very term in his diary. Mr. Hugh Simmons at the Fort Delaware Society knows the clerks name and he probably would share it with you if you ask him. Not all of the galvanized Yankees went out West as I'm sure you know. If a former Confederate joined the Federal military then yes he would have to take the volunteer oath of enlistment along with declaration of recruit papers. Because of the nature of the new recruit (former Confederate) a good physical descriptions would have been noted in his paperwork which is usually found on his volunteer oath of enlistment papers. With fold 3.com sometimes they are found in the personal papers section.