Thank you all very much, your information leaves barely a question open
But one more thought on the camouflage: Both, in the photo posted above and in Shore's book you can see that a lighter area of colour beneath the "B" on the fuselage has been repainted with a darker one. In other areas this was done with more care and is not visible. Could the new colour be Dark Green or one of the FAA greys?
Furthermore, on the photo linked above you can see (in my opinion) that a large area on the port wing has been left in the lighter colour (most probably Mid Stone). Traces of the same colour can be seen in the footrest beneath the cockpit. With all this taken into account, we would have a three-tone-camouflage here.
What do you think?