These are the snaps used to secure the convertible top boot to the inner rear panels.

I am missing 2 of them. I ordered from 2 sets of 4 from different Camaro Parts suppliers. One set was a sheet metal screw thread and the other was a 10 x 32 machine screw thread. The other suppliers do not list their thread specs and said they know because they come from their suppliers and there is no way to know without ordering it. I am not doing that again. RicksCamaros/Ecklers has a set of 4 but they want $33.88 and do not know the thread size so I don't know if these would work.

I measured one I have and it is an 8 x 32 machine thread and it 1/2 inch long. I found a set of 10 on Amazon that are the right and thread size and are stainless steel. They are $15.39 for 10 with free shipping. That is still pricey but at least they should fit.

I can post pics if anyone wants me to but I posted this as I could not find them any other way and thought it may help someone else.

 

I thing the problem you are running into is the boot is normally replaced when the top is and the aftermarket did all kinds of different stuff. Seems like each top place knew best and they came up with their own way of doing things.

Have you check the service manual or the assembly manual?

 

Fisher Body Manual would read what type of fastener.