11% of A-bodys in 72 had GY4 paint in 72. In 73, 1.3% had black paint.
In 72 they made 21,187 /6 Demons, 7,818 318 Demons and 10,222 340 Demons.
In 73, they made 11,315 340 Sports.
I have seen only 2 black 340 cars. One in Ohio had original paint.
Do the math, a black 340 Sport is a lot rarer than a GY4 /6 Demon.
Do what you want and have fun!