One additional option; find the discount auto paint stores closest to you, and start calling around. Some of them will custom mix a color if you supply a code, or they may be able to just use a sample. They will mix it and put it in an aerosol can for you. It's not crazy-expensive, I had it done about a year ago for less than $20.
You can use a paint for plastic aka "dye". SEM is a very good product and a auto paint supplier will have paint chips. However, for such a small piece that has little or no contact compared to a seat, I would make the correct color a priority and use spray paint over plastic dye if it is a better match.