See what Pentaxeros reports:
http://www.tiendapentaxeros.com/fotografia/pentax-full-frame-cuerpo-p-2244.html
Whom I consider is a reliable source as they are close to the official Pentax.
Well, I believe that the last lump of plastic thing is just to keep commercial secrets by the RP whilst letting interested users to know something is really coming soon, the testing prototype or even the beta machine should be more than that, in view of the launching date which is so close.