Yep, mine was wrinkled because I couldn't pull it tight enough to get the material hooked on the cleats front and back. It's not possible to install an OE-style perforated cloth headliner with the windows in. Not sure about the later '72-up cardboard ones.
I remember laying upside-down with my upper back on the package tray while prying up the window gaskets and shoving the headliner material under it as far as I could. It just kind of laid there bunched up and gluey halfway under the gasket lip and would move when you pulled on another section. There were a couple spots where I cut it too short too. It was a mess. I was really sore and pissed off afterwards.
I took that first replacement one out pretty recently and it looked like it was 53 years old, even though I bought it like 6-7 years ago. The edges were trashed from fighting with it. My windows are out now so I will get a better result this time. Lesson learned.