Tamiya COlors that come close

xf52 lighten it up with xf2
xf54 with a mix of xf20

Seems Like there is no Base Coat there Not the Normal Ones you see anyway.. Looks like METAL with Brown Camo Pretty cool really. But that is the colors I would Start with and Try and find a Match Note you wont get Exact but it can be close if you Exsperiment. Also MIst your paint coats and add more not only does it make the Paint more smooth but the more layers you add of paint the Darker it will be.