I've previously had access to the photos used in Dr. Martin O'Connor's book. The serial number on the side of the fuselage is per standard factory practice/style and stenciled directly on the plywood skin. It wouldn't be so legible if it were painted over the printed pattern, the dark blue segment would obscure the black paint of the stencil. Austro-Hungarian practice on the Albatros D.III (Oef) was to camouflage the upper surfaces of the wings and top of the fuselage turtle deck including fin. Initially the type 53 and 153 series were in plain varnish and uncamouflaged wings.
Godwin Brumowski at Flik 41j initiated the practice of having the camouflage finishes applied to top surfaces only w/ the series 53 aircraft delivered in the summer of 1917. This was done w/ paint and brushes or sponges. The fabric on this example is applied to the fuselage in the same areas, top surfaces only on/above the plywood seam along the top longeron, including the vertical stabilizer fin. After Flik 41j started the practice, applying camouflage finishes was done also at the Flep level.