That's not a very finished look! I bet there are plastic vent inserts planned for that area, but just didn't have them in yet and didn't want to hold up the delivery of the cars because of it. Eesh... Ask for them when they become available. (Or make your own covers.)
There is are detailed instructions on TeslaTap on how to add these lights. I found them a little complex, as they called for customizing the LEDs and using barrel connectors. None of that is necessary. If you know what you are doing, you can add beautiful LED's in less than 1 hour. The LEDs run under the lip that holds the parcel shelf.
Please read my post in this thread. There are links there to whatever you need to buy. Read the TeslaTap thread too for details of wear to tap into the wires and how to fish it through. Really, really easy.