Morning guy's, lunch time for me and a chance to join the fray!
I think it's the Dux-2 of 1913.
Not sure how that ties in with RR's clues as yet (other than Russian and pre 1920), going to have a look at that aspect now.
Found some info here that ties in well!
Dux Factory - Wikipedia, the free encyclopedia
Open House please if confirmed by
RR.
Good Challenge
RR, I had a couple of fruitless hours last evening and another trawl before work and at coffee break,Now for some food!