The big Greenberg book lists the colors for this engine as: "mohave, grey, peacock, state brown and red."
I've got a couple which certainly look like original finishes, but are dark green, very similar to the green of the 318, shown in the same book.
I'm guessing these are simply older restorations, but I thought I'd throw this out just to see what you all think; I can post some pictures if there's any interest...
Mark in Oregon
PS: here they are...
They are a slightly different shade of green; the lower one looks more "peacock" in the photo than it really is...