Update, I went to buy the "touch up" paint and different person told me the same as everyone else, there is no touch up paint for the Diamond Red color.
Yes, you can get the base color, however, you then need to cover it with a special red tint clear and then two other clears.
Another issue is that, the paint is not the cheap acrylic which is easy to work with, it's some other type of paint (can't recall the name) that he said was very expensive and very hard to work with.
If you use the paint to touch up with a brush there is a good chance it will be messed up and regardless, it will be very obvious.
I wouldn't recommend the diamond red color, especially if you drive on the highway where there is a strong chance of getting stone chips on the bonnet/hood.