I'm guessing you have something very similar or the same as what I have in my RV.
Does it look like this?
I don't recall any mounting hardware anywhere but on the sides where it mounts to each side of the shower. I think the top plastic/metal rail and the bottom plastic rail are only held in place with sealant.
You might try contacting Irvine Shade and Door or RecPro. They both make pleated shower doors.