It’s impossible to say without seeing that guitar whether the neck was ever broken. The other fellow may be correct; skin oils and the constant rubbing on the back of a neck can definitely act like a buffing machine and shine the finish. A break in a clear-finished neck is usually visible to one extent or another. You just have to look very closely sometimes. The good news is that a well-done headstock repair should have no impact at all on a guitar’s sound or structural integrity. Remember, guitars are already held together by glue! If it’s done correctly (and we’re not talking about a collectible vintage instrument,) a repaired break shouldn’t really make a difference.