The space bar in the FC660M is one of the main design issues that prevents this board to get more market. Also the windows and the right shift keys that are not standard sizes.
The colors you referred are the same I have seen, but I have one that came with dark gray PBT keys with pad printed gold legends, I do not think there is any other option.
If you want some alternatives in PBT, the Granite set is a great option. I am typing on an FC660M with a Granite set now, but the space bar is the original that came with the keyboard in dark gray. It is not bad, but it breaks the style of the set.
The space bar is the only "flaw" that I have found in my 660M.