Roger is correct--but It was not I who gave this idea. I have seen the pattern mold done--and done a few pieces of it. I have found for small holes that re-making the pattern is easier.
Yes, the grey is gel coat--and it is a Cook Composite so the colors should be available. Depending on how much needs to be done, I have found that painting is easier than gel coating--in this case it appears that the entire deck would have to be re-gel coated or painted It it was just a small amount, then the gel coat would be definitely the best way to go. With time gel coats do fade, and at times the original may not match....but will eventually fade out to the same as it is now.