Guys, here's a picture of a friends car. It's nearly a twin to mine. You can see there are screws holding the airbox to the hood. There are rectangular slots to slide a clip (just happens to be the same thing as the ones holding the seal to the airbox) into the hood to provide threads for a screw...no rivits. The rivits I need are the ones that hold the two outside sections of the airbox together, there's a bunch of them spaced around the outside of the two halves, my airbox has a large crack in it and the only way to fix it right as far as I could see was to remove the rivits and take it apart so I could work on the inside as well as the outside. The metal rod in the flapper door was bent, I think someone stepped on this thing once upon a time.
I kept all the screws that were holding the airbox to the hood when I dis-assembled years ago. It is a mixed bag for sure but there are about 4 I think might be right, coarse threads with a washer captured, I need about 18 of them and I'm sure the holes aren't made for rivits.
Thanks for any help.