Robert;
The engine in question is a prototype that never made it to the assembly line, ( this is the only one in the world ). The engine was part of Roger Wildman's estate, Roger wanted this and other engine's to go to John's museum. Roger use to set up at model trade shows and this was just one of his display engine's. Roger worked for / with Hi Johnson for several years on the .15 project as well as many others. You will find other rare Johnson products as you dig through the "stuff" in John's basement. His award winning pink Caprice is there too.
Blessings
Allen