The boat is finished with gelcoat, not paint. While you may be able to source matching gelcoat (possibly from a place like Spectrum or your Grady dealer), it's not actually going to match. It would have matched in 1982, but it no longer will since your gelcaot is now a different color than it was in 1982. Teh same will go for paint - the only way to get a true match, is going to be trial and error, swatches or sampling a section of the boat (if nothing is removable, you would need to cut a small section out).