I was a tire buster and then a mechanic for a Montgomery Ward’s Tire Center from 1975-1979. We featured Firestone Tires. You got everything right in your post. I do recall that someone would come in with tread separation and the tires were replaced with the same tire as part of the Firestone...
I have an air cleaner assembly from a 1970 340 Duster and the tin is red. The previous owner sold the car long ago but couldn’t remember the assembly date of the car. It very well could have been a surplus ‘69 pie tin used in early production of the ‘70 model.