When you find it, please let me know, I've been looking for the headliner board for models w/o AC for over four years!
I have finally decided to change out the headliner with the old "bow" style system. It comes as a kit with the headliner pre-cut, mounting brackets for the bows and of course the bows. You can choose the color of your vinyl.
http://www.automotiveinteriors.com/C...Headliners.htm
You should be able to find the trim pieces out of any lessor model Suburban. When doing mine, I did use sound deadener to reduce noise and keep in heat/AC.
https://www.sounddeadenershowdown.com/
Enjoy,