When I questioned the client about the original colours, the answer came within a second, and that was "green and gold symbolise money, and we are in the business of money". No matter how basic that sounds, believe me, half of the time, this is what designers are attempting to accomplish 'to relate'.
So the original hues were preserved and merely toned down to fit the essence of 'GYG'. Some other toned-down hues were added to the palette for accent use.