If a '71 'Cuda (BS) was originally painted: GW3, EV2, GB5, FJ6, GK6, FE5, GF7, GY3, or FC7 it was originally intended to have a painted grill STANDARD. There was no "way" to order/delete a painted grill.

Due to a shortage of painted grills on hand at the factory,
(during the winter, because a truck load of painted grills wrecked en route from Canada to Detroit)
"argent" grills were substituted as needed.

So, if your '71 'Cuda is: GW3, EV2, GB5, FJ6, GK6, FE5, GF7, GY3, or FC7 odds are it originally had a painted grill. Odds are higher early & late in the model year, with some "wiggle room" in the middle.