you need to take them a sample and have them scan it - maybe a painted switch cover? They need a piece about the size of a half dollar or so. Then be sure you use the same style of paint i.e. eggshell vs semigloss vs gloss. And then cross your fingers again.
p.s. if people smoke in this room the walls will be yellow and you're going to repaint the whole wall - same for kitchen grease.