Zoukei-Mura 1/32 Ki-45 Nick By Malcolm Reid, what colour are the drop tanks?

[GeoffSteer]

Hello-

  I have been reading with interest Mr. Malcolm Reid's build article on the Zoukei-Mura 1/32 Ki-45 Nick. I just treated myself to this kit which, I have been trying to resist for years. However, in the words of Oscar Wilde: "The easiest way to rid oneself of temptation is to yield to it".

One of the photographs in Mr. Reid's article shows the drop tanks, they are clearly a different colour than the underside colour. Anybody have any idea what this colour is?

With thanks-

Geoff Steer