It does look like 3 in the other pic. My gym had those exact plates. They were awesome the sound they made with each rep was cool.
So true. I started lifting in the early 80s and those deep dish plates where the norm then. Loved them and the rattling sound then and still do. These quite rubber plates are for the birds. In fact I can remember before I could use more than one plate on each side how quite they where. When I was able to use multiple plates and the rattle effect was heard. You knew you where on your way strength wise. Other people could hear the rattle in the gym and look.