Mark IX 3.8 Engine Color

I am looking into purchasing a 1961 Mark IX. However, the engine has gold metallic cylinder head covers instead of the blue metallic color. The seller has sent me a photo showing the correct engine # on the motor. According to the originality article shown in the library, the Mark IX has a "B" code cylinder cover in blue metallic. Does anyone know if gold was ever offered? Was gold ever offered on any 1961 model? I am concerned that the vehicle plate or engine is not correct. Any advice? See the image below.

Thanks
Cory