69 Notchback Mod Top $5000 Illinois. Marketplace NOT MINE
Here is what I have learned in my research on 69 Barracuda with 340 motors:
The 340 could be had without the formula S package or the Cuda package.
The formula S cars had the black tail panel with the formula S badge on it.
The formula S cars had the 340 S badges on the front fender, except if it was a side stripe car with the 340 callout. The 340 S badges were replaced with fish in that case.
I am not sure if this is entirely correct, but I believe it is.