I would agree on the std. 16, 12, 13, 62, 48 head issue that every ebay seller claims RA status, but would disagree that all D port heads can’t be called a RA head.

The late 67 – “97” head and the 68 “31” head was unique to the GTO/FB RA option. Both are D port, but were not installed in any other size or HP rated engine. I would elevate them to RA level. (And the price when they do pop up reflects it)