Rarity?

The slant six is very common for all A bodies. I have seen very few A bodies with power brakes, and few were ordered with front disc brakes in 68. That makes the mechanical end of your car fairly common. But, the chrome plated vertical bars in the grille indicate the car is a "Win You Over"/ "Success Celebration" 68 Barracuda. The notchback with this package of options would have also had red reflective tape stripe on the deck lid between the tail lights, rocker moldings and painted accent stripes (pin stripes), vinyl top, wood grain steering wheel, deluxe wheel covers, white streak tires, and either a Hurst 3 speed manual floor shift or console automatic. To my knowledge, the chrome plated grille and red reflective tape on the deck lid were only used as part of these special edition Barracudas that came out in the spring. Fastback and convertible Win You Over/ Success Celebration editions were trimmed differently than the coupes. If yours is one of the Win You Over/Success Celebration notchbacks, then it would be rather unique, but still not necessarily rare. Rare would be if it still had all the original package options including the accent stripes that are rarely replicated correctly.