I will look at my data for the 1996 Registry book, and get it to Jon Hanna ASAP for you to use. Maybe we can do it like a webpage here, for you all to review...
I wouldn't be 100% sure of the MCA rules, since as far as I know, they base most of what they judge on NJ and Dearborn produced cars. For instance, those east coast cars got a lot more black undercoating than the San Jose cars, and the antennas are different, and the trunk mats are different, too (this includes the '68 HCS cars, too). The list goes on and on...
The main reason I wrote the rules in 1996 was because (I felt that) CS cars were going to MCA shows, and getting knocked for not having the things that were on the east coast cars.
There is a gentleman, named Jeff (??) that did a Mustang Tech Newsletter out here in Calif., who is really into the colored marks on the underside, proper alternators, volt regs, belts, etc..etc., of the cars. I'll try to find that out for you.
I would like to see the GT/CS (HCS) cars beat out most to all of the other concours cars at shows, since we're the most aware and educated about what was what (in my opinion, and from what I've seen here on these message boards).
Besides, you folks are great!!
Paul.