I need to check my reference material when I get home from work, and at the risk of disseminating wrong info, (as I've been known to do on occasion... ) here goes:

In 70 and 71, JH23 was non-R/T, JS23 was R/T.
In 72, JH23 was non-Rallye, JS23 was Rallye. In 73 and 74, they were all JH23, and the Rallye cars got an A57 package code.