I had a pot metal one very similar to the first you show. Mine was I am about 99% certain just a toy ring or biker ring or premium ring. I believe I sold it in a bunch of toy skulls with some repro for not very much. Of course I am making no claims on your ring but mine was a very similar pattern. Second skull is interesting upon a closer look I think not the same as the one I have but still an interesting ring. I can not say I have seen one like it. I can see the RP. Is it an identifiable maker? Thanks for showing them!