Yes. It is common practice nowadays to paint the block black and leave the cylinder head unpainted. Undoubtedly the inspiration comes from the Rolls Royce engines and the Mercedes engines used for exhibition purposes.
However, Resedagrün is a commonly used colour for all types of machinery in Germany. It used to be DIN (Deutsche Industrie Norm). Ship Diesels, Kraftwerk turbines, lathes, milling machines, hydraulic presses, all were, and often still are, painted this colour.
Here is a picture of an M.A.N. Ship Diesel which gives a good impression of what the colour really looks like: