66 Barracuda Formula S - Performance indicator instead of Tach?

The number under the letter "C" on the fender tag should be a "2" if it's a Formula S.
Also the numbers under the letters "AB" should be "31" if it's an S. Having said that, since you have no fender tag did the car have the cutout in the left side of the rear valence panel for the Formula S exhaust? My 1965 Formula S has no fender tag, nor does the serial number begin with a "V" as all V-8 cars are supposed to. The only thing for certain is that nothing is certain, particularly with Mopars.