I am planning to sell an old Leica with the production number 5133. With that number it must have been produced as a Leica I in 1927, but it has later been converted to a Leica II, see picture. It is black, nicely worn, fully functioning with a 5cm/3.5 lens. I have seached the net the to get an idea of the price level to expect, but no where can I find this combination from this early (third) year of production. Hope somebody can help me, please. Thank!