Hard to pin down as it seems to be used all over the Gotha , with no real desiignation.
I got a number of variants of the color as well from diff manufacturers . just color matching so I can have a selection
WNW recommends XF 76 or Humbrol 90.
Here is a selection of the color rom Vallejo :

So far Ive used it on the fuel tanks , over brass:
