As of today, we have to wait a mere 37 (67) days before the world has concrete, independent, evidence of the existence of a hydrino-powered generator.
Another reason why Mills is almost certainly does not have a working prototype: no public record of testing - let alone certification - of safety, health, and environmental impacts.
This has been covered in many posts, both in this thread and its predecessors. BLP is located in NJ, USA. New Jersey has a long and complicated history with regard to both environmental (etc) regulations and corruption. However, partly as a result of several safety, health, and environmental scandals associated with industrial practices and waste (say), of the US States it's near the top, today, in regulations of these ... and enforcement of those regulations.
Whatever hydrinos are (assuming they actually exist), they are novel chemicals, with unknown safety, health, and environmental impacts. For BLP to have a working prototype of a hydrino-based generator, one that's ready for shipping to independent test facilities, it must have some relevant safety, health, and environmental certificates. And those - at some level - will be public. To the best of my knowledge, no such certificates exist.