I used to have one of the NOS metal valves mentioned here,,, back when I had my challenger and I saw NO WAY it would mount to the inner fender like the red/black phenolic valves does. I got lucky and found one nos valve in the 1970 part number box ( found it on ebay not to long after I bought the car in the mid / late 90s time frame ) and it was the red / black valve. Its what was on the car when I sold it

MY personal opinion ( Its worth what you paid for I know ) is the 70-71 had the bake light valves ,, metal came later.