There are two things to be aware of with original K-F or Willys color charts from various paint sources:
1. As time goes by the chips age and there is color shift, some colors worse than others.
2. Stock numbers or mixing formuli on the old charts are no longer useable.
PPG Automotive Finishes provides color match service to their jobbers at no cost to the jobbers. They just need the original paint color name (like Saddle Bronze Metallic) and the paint number off the firewall. They have their original reference samples in a temp/humidity controlled enviornment and a computer spectrograph that can translate the scan of the chip to colors currently in production. Note that the mixing formula is considered confidential information and jobbers are told NOT to pass the formula to customers. ICL Automotive (the former Rinshed-Mason) has similar type of support for their jobbers.