Exterior Paint Codes
The 2 or 4-digit code on the certification label indicates the primary or primary & secondary exterior paint colors. For instance, Dad's truck shows 2L 2K, which means the primary color was Maroon and the secondary color was Candy Apple Red.
And, note that there are two tables - one for US usage and one for Canadian usage.
US Paint Codes
Canadian Paint Codes
There is at least two anomalies in Ford's paint coding. As shown below, #2E is called Light Canyon Red and #51 is called Medium Fire Red in the catalog, but in the 1985 Early F-Series Pickup and the 1985 Light Truck Exterior Color Selection chart #2E is called Bright Canyon Red and #51 is called Dark Canyon Red. But, since both are code #'s they are probably the same color, and a note has been put in the respective catalog entries to show what the brochures say.