Penetro.... one of nine built by John Dopyera

This curious little resonator guitar is mentioned in Bev King's book, "The Dobroist's Scrapbook". In an interview with John Dopyera she mentions that he claims he built nine of these guitars with the "Penetro" label on the headstock before they were licensed to "Regal" to market under that name. So this appears to be one of the nine Pentetros, and it may well be the last one on the planet. I pulled the resonator long ago and inside, scrawled in pencil it says built by John Dopyera in a Los Angeles Guitar Shop March 1941 0r 42 I think I recall. It's been a while since I poked in there and I lost the only pic I had of the signature. I will retake a photo one day soon. I've been searching for more information and have yet to cross paths with anyone outside of Bev King that knows anything about these guitars. In an email to John Dopyera's son John, he mentions that he does remember a "Penetro" on his dad's bench. Even George Gruhn and Walter Carter have never seen one and only recollect hearing the name mentioned. It is still a solid little reso guitar, though cosmetically it has seen better days.