so judging from this photo the Ricoh rep didn't hide the name to well. If you look closely under the sticker you can see it's a K1.
I think PP is for Pre-Production. The number down is also interesting. I cannot see if it is 56 or 5b. If it is 56 it should mean that it is the 56th unit of the preproduction small sized series. If it is 5b, this could mean that it was produced on the final line of production but without the final production tools (A for small series in a workshop, B for small series in the final line, C for final products, BUT this depends on what kind of codes they use, so it's just a guess).