http://autocolorlibrary.com/cgi-bin/...ntiac-pg01.jpg
This is the web site for orginal paint available for cars by year. Found by searching the PY forums. If you stay with a 1968 GTO or LeMans paint color you will be able to enter top rated car show in the restored or alter restored group even if it is not the orginal color otherwise, you'll be always in the modified group which is large and very competitive. Good Luck