Even if you had the exact same paint, which I think may be laquer (you can take some laquer thinner and rub a bit under your rocker or other discreet area to see if any color comes off) you would never be able to match the color fade. If you're not down to bare metal you won't need primer, just scuff it and spray
If it is laquer, newer paints have had issues with bonding but this is just a bandaid temp solution anyway so I wouldn;t worry about it