no prob Senusret I.
the color of the fabric of the greek letters has to be a. gold by itself but then the gold must touch white. so the shirt has to be white. you cant get gold only letters on a khaki shirt or any other colored shirt.
now if you get the iron on greek letters, or the stitched on ones, you can get gold and white together, (at least at our greek store you can). usually we get the gold fabric with white stitching and then you can put that on whatever shirt / jacket etc color you want.
does that make sense?
here are some examples...
blue shirt with letters, white shirt with letters, black shirt with letters