Sorry never heard of them, but I've been out of the restoration business for a while. Slick website but download a PDF and no prices. Odd.
I did check National Parts Depot. A very established parts house with many warehouses over here. The door there is $324.19 for the metal one.
The I clicked on my saved website for a now defunct Mustang Plus (visited here, the actual business, many times and the owner was very into Mustangs. He sold his business a few years ago). Well the old saved website came up with Top Flight Automotive. Again a very slick website WITH prices. They have the trap door from Dynacorn for $275. I'm guessing a metal and USA product. Not sure.