PPG (Historical Library) typically is able to provide original or offset formulas for more old colors than can Dupont.
Nonetheless, the weak link to finding a Dupont or PPG formula is the experience of your local jobber and how much effort they want to give to finding a formula (from the "home office") for a paint that does not readily come up on their computer system. One nice thing about PPG is that regular people are able to contact the PPG Historical Library for information about modern "offset" paint names and formulas.
Tim
