If the color is embedded within the gel coat, I would make a highly educated guess that there is no such thing as paint codes for gelcoat.
That is because your hull is basically pigmented gel coat, not a spray painted hull with your colors.
Gelcoat colors are mixed in batches when applying the hull gelcoat to reach a certain color. That is because base gel coat batches has significant enough variations in color that have to be ironed out when making the batch.
Thus you cannot just make some generic pigment color to use, sell it and expect it to match near 100% against the boat hull because each boat has substantial variations in the color.
