Hi Ross,
I cannot say for sure, but I am fairly sure this famous D.III would have borne the factory camouflage of three uppersurface colors on the wings and tailplane/elevator: dark olive green, Venetian Red (reddish or chestnut brown) and a light green (mixture of pale Brunswick green & white). Although these three colours do not show up distinctly on the available photos I can quickly find, this is often the case in various lighting conditions.
I think very little modification was done to this machine before it was captured. The rudder was clear-doped fabric and the fuselage appears to have been natural-varnished plywood, with no painting on the underside. There seems to have been a metal cover over the fuselage at the rear section of the machine guns. There was a rack for flare cartridges on the right side of the cockpit, and apparently a downward-firing flare pistol was installed just above a protective metal plate applied to the fuselage. See the "Albatros D.III" special by P M Grosz, from Ray Rimell.
Greg VanWyngarden