Mercury places the paint color code on the drivers door jamb. On the color plate, the code appears near EX PT (Exterior Paint), typically above or below; sometimes the actual color is embossed on the plate and not where expected. The typical format is WT/M6640, but the M6640 part is rarely used and often only WT appears. WT corresponds to Performance White Clearcoat. Pre 1970 Mercurys can be problematic due to same-name, different-color issues and different codes.