The engine is normally finished in a medium Brunswick green , that's for the 6 cyl. version anyway . The stationary engine guys use a similar green .
http://mmoc.org.uk/mbimage.php?src=1359987041_17022
Regarding the brass data plates, I have new repros that were done in the UK somewhere. R. Ballard kindly sent me a few , the larger MCC one with the engine number , chassis number and axle/gearbox details and the smaller ubiquitous one with the contract number , this smaller one seems to be used on most WW2 British vehicles.