Tokyo Marui M16A2 Receivers Colour

[Piecemeal]

Hi all. I'm new to all this and I thought this forum would be a good place to ask this. Can anybody explain why the Tokyo Marui M16A1 and A2 upper/lower receivers are grey in colour? I've been thinking of buying both simply as disply models for my 'mancave' and apart from the above mentioned it seems like a very attractive buy. Can receivers of the correct colour be purchased elsewhere? Or has somebody found a way of changing the colour? Any advice would be helpful as the colour takes away from an otherwise attractive looking piece of gear.

[mightyjebus]

The original Colt M16A1 and M2 are actually anodised grey in real life as it's a protective coating.