Just trying to get this straight: you have a 67 notch... you need rear window trim? or a gasket? or both? The 67 gasket has been available off and on, but I think it's not available right now. It uses the plastic lock strip, as you know. The lock strip is an extrusion so you could perhaps buy a kit for a fastback and trim to length if you can't find one listed for a notch. You also need the corner pieces which are often missing but which you might have.
The other option is you could use the 68-69 gasket, but then you need the 68-69 notch stainless molding, which is a very rare beast.
What's the current status of the car? Glass out? Seal shot?