It will be pretty hard to tell from pictures they are just plastic and glass after all. As a start maybe some images of the markings on the inside of the arms, the RB engraving and general pictures may help. The engravings are on the outside for all Raybans I own (either B&L or Lx)
The key is the quality of lenses and you can only really tell with them in hand
Any idea on what lenses they have? B15, G15, polarised?