Just read about a product called FLEX-MOLD on the Pearson-boats group. It looks like a clever product that may be used to match the gelcoat pattern when doing repairs on non-skid deck surfaces.
Here are links for the product and a pattern that has been recommended for Pearson boats. I have no experience with it yet but I wanted to document it here to share the information for future reference.
Jamestown Distributors + VideoFLEX-MOLD Pattern