So basically the last part of your last sentence means that there is no way of accurately determining real from KO as KO can now be the same quality as real? Were there any colour differences between real and KO, for example I draw your attention to here:
http://www.cobraislandtoys.com/tf/1987/rodney.html to the Lodoni headmaster. All sources indicate that the plastics used are coloured yellow for the limbs and blue for the body, but I have seen what I expect to be the real thing with yellow limbs and a more of a purple body.