Need help with a few '68 Dart fender codes

I was thinking the same thing. I probably looked when I got the car in 2015. I'm going to check after work tonite.
Commonly under the a in the top row is a 6 denoting a console. This would probably be accompanied by a 4 under the b indicating bucket seats. Since there's no 4, there's probably no 6. I'm curious to see what might be there.
It's interesting to see the Spring Special options with no radio (I think).