That was probably the idea, but mine still needed some modifications. It can't get any tighter to the roof than where it's screwed in with the dome light, and mine was still too long to tuck under the windshield gasket. You can force a little more bend into it as you add all the trim and stuff, but it only goes so far. Helps to install it when it's warm too. Better for the headliner anyway, not so much better for whoever has to install it (it gets HOT in there!).
They're pretty close but between assembly tolerances and aftermarket parts I'm sure most of them could use some adjustments. Probably was true of the cardboard ones too, they're just easier to modify.