Is thefold down rear seat one of the rarer options for the 69? A buddy has a 69 Z/28 RS hugger orange , White vinyl top deluxe white houndstooth interior ,fold down rear seat ....
You can go to the CRG main page, click on the "Options" box in the grid, then find and download the RPO spreadsheet to see how many were sold in 69. That document is good for a lot of other questions you may have in the future. Make sure you read the notes also to fully understand the numbers. From above, looks like the RPO code is A67.