I'm guessing they can make you up a small batch of color matching paint that's the same type of paint they use for touch up
rims... I'm not sure what it is, lacquer maybe. Paint stores have all kinds of paints for which they can formulate something good for touch-ups.
There are also auto body supply stores that probably do it too. I remember some years ago I had to get my car painted and they took the color fuel door off the car to help match the paint.
And a bunch of auto body shops that make their paint also have the digital color matching equipment. If you go into one of those shops and talk to them, I bet for a few bucks they can make you up a small batch of touch-up paint.