I think I have found my own answer. In the Book Diesel Demonstrators the FM H15-44 has a brass nose PLate. Also in FM in Color several early FM H-15-44 have what sure looks like a brass nose plates. I think very early H-15-44 have the brass plate and later engines had the Aluminium nose plate. Since the plate came from the factory , I know it is not a recast, but may never have been on a engine or was only on for the NJ Railroad show.