I suspect that the chrome bumper and white paint on the roof were part of the CST package too. In 67 the script on the door was "custom" and in 68 the script was "CST". Interesting that the "custom" was the high end trim package in the 60's. Post 72 the "custom deluxe" was the base package.
Lots of strange things happen at the factory. My Chev that I bought new in 1980 has a GMC steering wheel. The dealer told me he has seen Chevs come from the factory with GMC tailgates.
