Yes, I purchased them through this company:
https://jcaparts.com/products/1955-1964-gm-rear-window-reveal-molding-clips
They're also sold on eBay through the same company but I just purchased them direct. They aren't exactly the same (there's an extra hole in the aftermarket) I've attached a photo for comparison.
I was hoping to see if someone had a source for the front upper corner clips for my car (second attachment style in 55)?