It's only found on 1970 E bodies from Hamtramck as far as I know. I have owned quite a few myself and have personally seen hundreds . We used to comment on the 'Rock' signature way back 25 years ago . I am sure lots of research has been attempted, and even a magazine article or two has been written about it, but I don't think anybody has gotton to the bottom of that story (?) as to who Rock was .
