How do you know if a 66 barracuda is a formula s or not?

1966 Barracuda with a Formula S option had a 7 for the option code also. I dont know what letter it is under on the fender tag but it might be the same as the 67. Seat belts with retractors were also a 7 on the code list, Formula S package lists ---273 Commando 4 bbl, suspension package with HD rear springs, HD torsion bars with sway bar, firm ride shocks, tachometer, 6.95x14 Blue streak tires, HD wide 14" rims, 14" bolt on style wheel covers, and the Formuls " S " fender nameplate. I have both a Formula S with air and a non S with the Commando 273 and air.