In 1964 it wouldnt have been painted, its gelcoat
If its been painted before, no idea what color that might have been, but its likely changed colors slightly since it was painted. So even if you knew exactly what paint color was used, it probably wouldnt match now.
Same for gelcoat, it changes colors slightly over time. Color matching gelcoat is tougher then color matching paint, as it changes more then paint does as it dries.
As you didn't post any pix of what the boat looks like now, I'd suggest you paint or gelcoat everything below the rubrail. That way it does match.
Same for the topsides. Paint or gel everything