painted mine using 'myford grey' from a firm on ebay
probably and most likely the wrong colour. but i dont really care. it had previously been repainted by the previous owner using hammerite black with a touch of white mixed in 
it now looks 100% better than it did before and right or wrong colour, i like it. and thats what matters most….
and like you, ive seen them all colours, and i mean ML7s only, not all models which i know are different colours anyway.