Heh! I asked the same question when I started mine, and the overwhelming reply was dunkelgelb, but panzer gray wouldn't have been impossible since this is right around when they started the switchover.
As for the pic, hard to say. Black and white does funny things to colors.
FWIW, I did mine with a dunkelgelb base:
On the Bench: 1/32 Trumpeter P-47 | 1/32 Hasegawa Bf 109G | 1/144 Eduard MiG-21MF x2
On Deck: 1/350 HMS Dreadnought
Blog/Completed Builds: doogsmodels.com