Your question got my curiosity about the trunk mats. Years ago I added an aftermarket one but discarded it when it promoted rust from trapped moisture.

If I'm right, my 1972 parts book shows that there were four different trunk mats in 1968. Apparently they had mats cut to accommodate the mounting bracket locations for both Space Save and conventional spares in both coupe and vibration dampener-equipped converts.

It would be nice if the repro mats came with templates to show where to cut for the options.