I bought the 71 NYer from a person I knew and was from my town.

He was an older gentleman who bought the car new and was not one to lie when he said
the engine was as he bought it and ran fine until he had to give up driving because of eyesight problems

The rear baffle as you see does not look like someone cobbled it together, it looks purpose built for that application.

I am of the opinion it is stock.

My 2 cents....Joe

PS the rear baffle is sheet metal, It just looks like a thick piece of steel.
I had to be formed in a die specifically for that part.