As you said, it was only possible in later versions. In the old times those helmets were only traded by the following NPCs: Cornelia (Carlin), Azil (Darashia), Kroox (Kazordoon), Hardek (Thais) and Shanar (Ab'Dendriel). Viking helmets also by Timur (Fibula), and brass helmets by Gamel but he only sold them.