It is actually a rubber part, to seems to be original to some cars: here's an pic from the BMW own tech manuals:
It's an e3 part as it has at the bottom an edge of ~10mm towards the engine + a flap with three lips pulled through. E9 doesn’t have either of them.
Also note that is appears to have 6 slats, but at the front there are 7 visible, the top vent opening is closed from the back. That is why counting fins /openings in confusing to many.
Here's the image from the tech files of the E3 part where you can just see the top opening is closed off.
Also The e9 face plate ends in a simple vertical plane, with a ~10 mm lip at the bottom, pointing towards the rear of the car; going under the shift console. see the link below from Markos Repro parts.
The lower edge of an E3 part folds forward, not backwards as E9.
View attachment 202692
with link to the pic origin: