Where was this "GTS Line"?
Same assembly lines built /6 cars to 383 GTS's.
That's how you find 318 car with hemi car buildsheets. The two cars had the same color interior and near/next to each other on the same assembly line. So the line worker just picked handiest seats the color they needed.
If you delete the trunk GTS emblems and trunk trim, the whole trunk lid is different. Sheet metal was pre stamped for holes required for emblems and trim. So the bare trunk itself was not an "GTS" trunk, it was a 170 trunk.
GTS roofs without vinyl roofs did not get the medallion on the C pillar. (IIRC, only vinyl roof cars got medallion)
If you just deleted the "* Roof Drip Edge Molding" there would be a gap between the front and rear drip rails. You can see in the delivered Darts, there is not a gap. So they put the lower level 170 drip rail corner pieces on the bare body prior to primer.
When you look at all the items substituted, and swapped between models, swapped body types (conv frt frame plates?),and just left off....it's just a conglomeration and combination of parts.
The shell delivered to Hurst was unique and specially made for this project. It's no more one thing, than less of another.