@aearch ; I'm intrigued by your source. Could you please make & share an up close picture of your headliner, so we can see the lines and shape of the holes (perforations) in it?
SMS got their original CSL headliner pattern from me. When I was restoring my CSL 3 years ago, the original headliner material was tattered. It had been removed, but the PO saved the old original material in a box. The PO had purchased some new black material and installed it in the car prior to my purchase, but it was incorrect. I wanted correct. The black SMS material is as close as you will find to original black CSL material. I looked worldwide in 2016, and only SMS would make a small run. I cut a small square out of the original headliner and sent it to them to copy.
Coupeguy in Colorado may have some of my material also. He bought a decent amount when I had it made. (This wasn't a money making venture for me BTW!) Try coupeguy.com.