I’d be inclined to take the bike to a good quality automotive paints supplier and ask them to mix an exact match of the paint on the bike. They can then fills some good quality aerosols with the paint that matches the paint on the bike. The paint on the bike has almost certainly aged and even if you find the paint code, any paint that is mixed purely to the paint code probably wont be an exact match for the paint on the bike.
Matt paints are commonplace now so any good quality automotive paints supplier should be able to supply something that is a match for whatever HD used.