Man, I feel your pain in looking for these clips. I just did paint and body on my 68 GTO and when I went to install the new vinyl top, I was missing 2 of those clips. Is that clip for the bottom part only or is that clip used for the upper hole as well? I did a google image search of that clip and I found that Autozone sells a clip that is similar. I'm probably going to order it and modify it by adding the part that slides under the lip of the back of the molding. The clip that Autozone sells only comes in 50 count. If you want, I can send you a handful of clips once I get them. I found a few clips on a Facebook page but they were so rusted that I'm pretty sure they would have fallen apart once I tired to install them.
Here is the link to the Autozone clip.
https://www.autozone.com/p/auveco-mo...-23691/1410694