How is this one supposed to be installed?

[Fabrice]

Busy refreshing the interior of my 73, I came across a tiny prob I forgot about.
Last time I did the interior (20+ years ago), these two plastic covers on the rear plank were loose and I never seen them installed correctly.
I did use at the time some long screws that basically kept them in place going thru the headliner. Not the right way at all, but they stayed in place for 20 years.

This time, I'd like to install them as they should or better, but wonder how they should be and also what kind of screws/hardware they need.
On the car side, as tested, the only contact they get is a plate with spikes where the headliner is tensioned on. As there are no screw holes in it, is there some kind of hardware supposed to be in front of that plate that is missing? 
I can of course drill that plate, add long screws and forget about it again for another 20 years,
but if anyone knows how it's supposed to be, I'd like very much to solve that mystery!

 

[Fabrice]

Nobody around with a coupe and a screwdriver who could tell me how that thing is supposed to be installed?
 

 

[Bentworker]

Nobody around with a coupe and a screwdriver who could tell me how that thing is supposed to be installed?
 

Nope- because my coupe is in about 1000 pieces!

 

[c9zx]

There should be hole on the end of the lower and upper headliner retainers that the screws go into. Try using a small needle to find them, it may take some time. i'd use the shortest screw that works. Search the AMK site for Ford part number 377537-S2. Keep up the good work. Chuck

 

[Fabrice]

Thx guys,

I've looked in detail last nite, there are no retainers to be seen. No holes either, tho, there are 2 but way bellow the height where they should be. 
Prolly why they always been 1/2 way fixed.
No prob, I'll manage something.