West Coast Classic Cougar has that patch panel. I repaired the drivers floor in Ginger with one.
Edit; WCCC only had driver side convertible patch panels listed as in stock and does not have coupe patch panels listed at all. They did 6 or 7 years ago when I did my repair.
I believe these are a different panel than the one that Horse Heaven was producing a few years ago. This new pan has better defined ribs / channels, from what I’m told. Also, I believe Horse Heaven Mustang Restoration is no longer in business.