For dents use a light weight filler and spot paint. Automotive paints have "blending solvents" that can be used to hide the repaired edges. Sometimes it takes a fine touch.

If there are a lot of spots, repaint the whole thing. It will be easier and give a better result in the end.

For gel coat, getting an exact color match can be a problem. It relies on the skill of the individual. Unless the manufacturer just happens to have some of the same batch that was used on the boat in question, it is pretty much hit or miss.