From what I'm seeing in the illustration and your photos there's a missing LARGE wingnut to hold down the spare and jack hook first and then it appears that the small wingnut holds the cover inside of the "cup". See the small wingnut and "cup" in the upper left of the illustration and then the larger wingnut by the jack hook. And I also agree with the spare with the whitewall down or upside down as most like to mount the spares which is how I think they should be. My '69 Road Runner I ordered and bought new in '69 had the spare tire mounted redline down as I used the back side up sort of like a bucket or cup to hold stuff like a spare "can" of oil and oil spout, and a can of simonize wax and a few rags to check the oil and wax the car. Lots of other stuff was easy to put into the upside down spare to keep it from rolling around the trunk especially with the 3.91 Suregrip and tire hookup

From a '69 factory "sales features" slide show, not saying this is correct but that's how I remember it..........and yes I had to check to make sure I got a redline spare first thing

Mike