I think there was a good deal of variation; the photo record seems to bear this out.
Somewhere buried deep in Koloman's aerodrome OEFFAG D.III build log there was a long, detailed discussion about the lumber that was available in wartime Germany, as well as the species that were favored for propeller making, and what was substituted for same after the inevitable shortages. IIRC the dark/light laminate props weren't for looks; it was an exigency forced by lack of ideal lumber, so a compromise was made combining a fairly lightweight species, with a denser, stronger one...