The 71 Barracuda (318 with AC) that I now own was purchased by my father in October 1971 with 13,000 miles on the odometer. The SPD was 115. It had the metal control valve. I know that for a fact. I was a teenager at the time. My dad and I worked on the car. I remember when the valve failed. Now, could it have been replaced during the first 13K miles? Possibly, but I doubt it.

In 2014, I purchased another 71 Barracuda (318 with AC). I bought it from the original owner with 116,540 miles on the odometer. The SPD was 625. In his garage I found a big box of junk that included the original carburetor. Also in that box was the red-black control valve that I believed to be the original.

I believe that during the 71 production run, the valve was transitioned from the metal style to the plastic style.

David