What’s the exact process to identify a real 66 Formula S Barracuda?

I'd have to check the various materials I have collected, as I'm trying to recall if the 150 speedo was a separate option, or came with something else?

Maybe it just came with the trip, while the 120 trip was optional.

Also, I know 67 was a slightly odd year, different parts and pieces and different standard items. Such as the speedo cable was screw on.