OK, I think it's coming together...
The white car pics were just pulled off google. I thought they were the same car, but I now realize that the top pic is of a later TR3...because of the fact the boot floor is raised for the wider sized tire that has to fit the spare holder. The bottom white car is a TR2...or very early TR3, told by the flat boot floor. So, I have learned how to tell the difference by the boot floor!?!
I know the post 60K bodies had the 3 larger tabs to hold the bottom of the cover.
If the red photo is a mid production TR3, then we can guess the single thin tab was added to the boot floor by 41k. This is apparently a long thin strip.
When I look as closely as I can to the imgur.com pics, I can't see clearly any tab. It appears the cover has a 90 degree fold to the rear, and the retaining screws go downward into the boot floor. Soooo....I think we are back to the assumption that the TR2's have no metal retaining strip.
That said...I then wonder if the screws going down and INTO the spare tire compartment didn't cause a problem. Like perhaps puncturing the spare if they were located wrong?? Thus prompting the metal strips to relocate the screw horizontally??
PS...I was looking through the pics, and I see the unobtainium fuel line clip you were talking about on the 3rd pic in the album!