Hey, so, sorry to comment here, but you were curious about having nameless gallery folders? It is not a core membership thing. Just go to your main gallery, edit page, pencil on any folder and edit this widget. Then check the option remove name for custom thumbnail.
Once again, sorry this wasn't on the page you asked about it, but I can't post there! Hope this helps, if your still looking for an answer! I've done it both accounts without core!