A friendly mole of ours ran this handset's serial number through an internal Nokia system and has confirmed it as a Nokia prototype. He was also able to uncover an RM-680 product type classification (further distancing this from the RM-626 slider) and a 0595571 product code. Add those to the "Prototype Build B2" and "Property of Nokia" labeling inside the phone's battery compartment, and you've got yourself a very strong candidate for the real deal here.