"original colour code for the red Commando" is probably not repeatable in today's modern paints. In other words, back in 68 that tank was painted with either lacquer or enamel paints, which don't exist today in modern formulas. If you could find the code, you could maybe find someone to mix it up in a state that still allows it. For example, I was able to have some lacquer for my wheels and dash mixed in Nevada, but not California. The paint store said the pigments were not as good as they used to be and starting to disappear from the market. When I restored my 67 Firebird, I thought I could take the GM paint code down to my local paint store and have it mixed up. Boy, was I naive. I was able to get five swatches of what they thought it was painted on metal strips. Then I found a metal piece on the car that had not faded over time, and had a color expert (architect) eyeball it and make the best choice. It came out pretty well, but not perfect.