1989 Chrysler New Yorker Mark Cross Edition - leather roof

[Tuxster]

Hi,

I have a 1989 Chrysler New Yorker Mark Cross edition in very fine
condition except for the roof. The old leather portion of the roof
has faded and is peeling away.

What is the material directly under this leather (what the leather is
glued to)?

Looking at it and feeling it, I'm guessing it might be fiberglass, but
I'm not sure.

I don't want to pay hundreds of dollars for a new roof, so I thought
I'd just sand it, prime and re-paint it myself. (Note: only the back
third of the roof is covered in leather. The front two-thirds is
regular hard top.)

So, before I start sanding this down, is it fiberglass or so other
material?

Thanks for any help!