If you're painting the entire thing, why do you care if the paint matches the original color? Even if you had the original color, it wouldn't match after 22 years of fading from the sun.
Either pick a color that matches the accent colors of the boat, or find any gray paint. Yamaha grey would work fine, I'm sure. Nobody is going to notice that it's not 'Damascus Gray' specifically.
Life is hard enough, no need to make easy things difficult too.