'66 Sure Grip ID?

The '65 Barracuda S I inherited came with lots of parts and pictures. Sometime in the early 80's my uncle bought a wrecked '66 Formula S and striped it for parts, engine, 4 speed, and the rear end among other items. If I've read correctly the '66 came with the small sure grip? Is there anyway to ID it from the outside or does it need to be opened for that? I assume that the little tag isn't enough to go by because I see they're still available new and could be added to any rear.

This is what came with the car, and also a poor shot I took today of the rear in the car. I don't know if he switched them or not?


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