Difference between 67-68 barracuda doors?

I just be darned if I know. I guess yours is a fast back. I've never owned a fast back.
A 67 notch back quarter glass has a stainless piece on the forward edge that accepts a weatherstrip. Vert does too. Does the fast back have only a raw glass edge there in any or all year models ? I dont know.
The one screw or plastic plug in the upper door I was looking for didn't appear in any of your pics.