What’s the exact process to identify a real 66 Formula S Barracuda?

I once owned a 66 Formula S. It had the 273 Super Cammando, auto with the console, 7 1/4" rear end. No sway bar, no disc brakes, and no way of knowing if it ever had these options sue to it being lost in an ugly divorce.

I have been looking to replace that car for over 20 years. I recently found a "Formula S" car and was seriously considering buying it. However, after seeing the fender tag I found it to be a non-S 273 commando car. No sway bar. No disc brakes (which I thought were an option) and no 7 under the F.

My question is....even though I want a true Formula S car.....are these non-S cars still valuable? The one I found is being sold as an S car and even has the Formula S emblem on the fender. Any advice would be appreciated. If someone knows of a 66 Formula S for sale....please.....do share. I am ready to scratch this 20 year itch! Thanks!