Six pictures below.
The first three pictures are of a tire with no DOT stamp. I found this from someone who claimed to remove it from a Mustang in 1980, it was a spare tire. Note the last (7th) picture of the steel rim date code. I don't have pics of the valve stem/cap and weights handy, but can get them. There is no "SUP-R-BELT" lettering on this tire. It is as close to an original that I have found, and at this point am keeping it for my spare tire (unless/until I find something better!) I've included it here to promote dialog - perhaps this is not an original...
The second set of three pictures are of a tire that does have the DOT stamp. It includes "SUP-R-BELT" letters, unlike the "original". Note the tread difference compared to the "original". I have two tires like this, and would certainly sell one or both, $60 each. Note that there is some rubber splitting going on.
MODIFIED - added four additional pictures from a 68 GT with 4K original miles (the one with dealer installed wire wheels). These don't have SUP-R-BELT letters either. They do have "Deluxe Champion" which the "original" tire I found does not have. But this is a 68 not a 67, and all things are subject to change. This exhausts the research I've done on the subject.
