Nate, this helps a lot....
- looking at the detail around the gas filler cap (for the first time), I just have to think yours is original and in great condition. At least, it looks like there is a kind of meticulously sewn 'collar' to fill the depth of the carpet, unlikely attention to a replacement..and the backing looks similar to the "fuse cover" piece from 8ma1046.
- I have been trying so hard to reconcile the grayish color (in 8ma1074 and others) against the black of the interior, and am coming to the conclusion that both must be right. At least, that 'mystery' carpet piece must be original--at least, I have to believe that my foot carpets were replaced in the mid 80's (they are single long pieces, and no grommet snaps to hold in place) and though the correct footpad is in place, the cutout for the headlamp lever (and thanks again 
was missing (along with the lever, and thanks again ). but the only way to explain the wear on the mystery cut is that it was there a long time, lets say 15 years and 20+k miles...
Even though 8ma1074 was immediately before my car (and even, has the AC condenser bracket from 'my' car), it just appears that DeT had so much live variety in what they shipped...! M!ke, your car is/was so original, maybe you can break the tie...!