That's surprising to me. Did you go back and count your back issues, or read that somewhere?
Because I counted six A bodies on the covers in the twenty nine issues sitting on my dresser (one issue had two, so I counted both). I find it hard to believe the other six A bodies are spread over 130+ issues.
In the issues I sampled, I did see two late model rams and three '50's customs, so I agree If you're saying the A is under represented, but 12 seems a stretch.
And I'm just about positive I have seen a demon on the cover in the limited collection I have.