Tim, there were two different rad grille mounting methods, due to the rapid time between conception and production of the Pantera, it was belatedly found that because the front trunk was a sealed space, if the bowden cable that opens the hood breaks or becomes disconnected, the hood cannot be opened without cutting your way in. So on later examples, bolts & nuts were used that allows removal of the radiator grille and thus (difficult but possible) access up to the hood release mechanism. Think of this when you install the grille on your car.
Later still, with the release of 'L' models in Sept.1972, an official TSB (Tech Service Bulletin 9, article 64) was released that recommended installing a second short aux. hood release cable that attaches to the hood release mechanism, and goes thru a grommeted hole drilled at a certain spot in the toe box from the front trunk, so it hangs above the accelerator pedal. Thus in the event cited, the hood can be released much easier than removing the rad grille (or worst case, cutting). An 8-1/2 X 11" 98-pg illustrated book of all the Ford-issued TSBs for the Pantera is available from the U.S vendors, or can be found in the POCA Archives as a downloadable PDF file for POCA members.
Owners also found that if the hole you must drill for the aux. release cable is made about 1" or larger OD instead of only 5/16" as mentioned in the TSB, it makes a convenient outside access for removing one of the tiny circlips that retain the clutch master cylinder actuating rod pivot pin (to release the clutch master cylinder for service), which is otherwise often a difficult job due to very limited access & visibility up under the dashboard. If necessary, a plastic cap-plug of a size that fits your big drilled hole (with a small hole in the plug for the aux. release cable), will block the small amount of warm radiator air leaking through the large drilling. Plastic cap-plugs in std sizes are available from hardware stores, or the vendors. Welcome aboard.