Have the paint color matched to something like the door jam that isn't faded and generally beat to heck. Mixing the color per the color code, which by the way should be on the firewall, is for lack of a better term "generic". In other words, the color a paint shop mixes would be a close approximation, but will never match what was on there originally. By the way in case you didn't know most paint shops can match the color and package it in spray cans. Handy for fixing trail damage etc. You usually have to buy a minimum such as a pint that around here translates to three rattle cans.