I have seen that photo on the photographer's OF so if it is fake then the photographer himself is to blame.Sorry, but the one with the cock is fake. Check out the lighting on the penis compared to the light on his right hand. Obvious fake - the darkness of the penis (especially on the shaft at the top) is too dark considering the rest of the lighting on his skin, especially on the hand behind it which is much lighter.
I do see what you mean, though, in terms of the colouring.