Ever see a BLACK/ORANGE 71 340 Duster??
Can't say for sure about the 71's, but the plaid benches were standard in the 72s. Besides the orange, like the post above, I have run across green/yellow, bright blue/dark blue, and the black/white that I have. The plaid seat inserts are cloth, the rest vinyl. These were not limited to the 340 cars. Legendary still has some of the NOS plaid available.