Cobraman,
If your car came with the "GT" option, then it came with Argent wheels. Argent wheels where standard with the GT backage, however you could change them for chrome if you chose to. And you could add chrome wheels as an option, only difference was the wheel cap did not have the "GT" emblem on it. As far as I know, you could NOT get the argent wheel as an option by itself.
If your car is not a GT, you could get any wheel cover option.
Doug