Not sure a Plymouth would get a pie tin in 70. My 70 383 4bbl ac charger had no pir tin. Plymouths would of had Commando tins, not sure they were on 70+ cars.
My '70 383 4 barrel AC JH Challenger has an orange 383 four barrel pie tin. I always assumed it was correct but got the car 20 years ago and can't say it originally had one. I'd hate to find it didn't, the air cleaner would look sort of nekkid without it!