I never did and still do not understand the reluctance of being listed or identified in the SAAC Registries.
Apparently it varies according to the year and model but for some reason 68 GT350's seem to hold a special revanence, i.e., a special secret appreciation for that?
Here is one reason. My car was in the 87 registry(all others since) and a guy comes knocking on my door in the early 90s at night. It was one of the Rick brothers from Rick Ford here in Mi. Seems he ran my VIN through the SOS and got my name and address. Did I get mad? No. I showed him the car and he gave me his info. It seems he ran a LOT of Shelbys through the SOS here in Mi to get their locations. That would be a great reason why someone would not want to be in a registry. Now about that FBI agent that came knocking on my door back around 1988 that is another car story.....
During the pre-publication days of the '82 Registry, Howard Pardee had already gone the route of the DMV's.
I don't know if Howard was responsible but shortly after/during it, California passed an anti-stalking bill where DMV records were no longer Public information.
There was some rhetoric and "discussion" but in California's case, it is probably more about "celebrates" complaining about exposed privacy.
An added note, we are so used to having data at our fingertips now via the Internet, that it is difficult to believe that only maybe 1/2 the states DMV records at the time were on any kind of an "internet computer system". Meaning even if you could still access information in a state like New Hampshire, you couldn't get a print out because the state system didn't have the capability.
OK. You are missing the point here I suspect? Why is it that just '68 GT350 owners are afraid? Get it yet?
Also, considering that there may be blank spaces in any year of the "Registry", it's more likely that there is either no FORD information available about those cars or the particular Shelby Registrar, just hasn't received it as yet?
It does seem that Marti has it.
"As it was in the beginning, so it shall be for always". "WTF is the SAAC Registry and WTF should they be entitled to the information?" That's the feedback that I get often with quite hostile tones.

This is an old battle and frankly I was done with it 20 years ago. It's not going to change anytime soon.
"The Registry" was/is done in good faith and there will ALWAYS be anti-vac'ers out there with their own "special" reasons for not participating. Maybe they see it as another fascist deal and they like 'Hells Angels' are the only truely free Americans left? Who cares at this point?