TLDR: 2021 KTM Duke 890 R. YES, it fits. Yes, all bits you need are included. Yes, it's high quality metal and pretty nice, USA plates will require little included adapter arm things because the bolt holes are too wide. This is not great, but it's fine.
Details - The kit itself is metal, it's basically built the same as the stock piece, only the stock pieces is that high-tech plastic, like roller blade chassis are made from - this kit is Aluminum, probably?
All the bits you need are included - the brake light they give you is smaller than stock and the LEDs are very pink. YES, the included brake light also illuminated the license plate, has little LEDs under it for that purpose. I like the stock unit better, but the stock one is too large to use with this kit.
Instructions:
Follow the pictures they pass off as instructions and just to save you some time with those bullet connectors for the brake light -
YELLOW->RED
BROWN->BLACK
GREEN - >YELLOW
Turn indicators have colored dots, Red dot is the RIGHT indicator.
You are now all set, assemble it the same way you disassembled the stock piece.
BAD THINGS:
If you are reusing your stock turn indicators you will have a bad time. The instructions assume you are using aftermarket indicators with a LONG wire on the connector, so the included brake light has a LONG wire on the connector, you're meant to pull all these long things through to under your seat where you will hook them all up to the stock harnesses. THIS WILL NOT WORK. There is insufficient room in the body of the tidy to store all the brake light wire and the stock indicator plugs are too short to pull completely through the tail tidy.
I solved this by whacking off the majority of the brake light connector wire and just attaching new bullet connectors. This mostly works, it's REALLY tight to stuff all the wire inside the unit, but it does work. If you straight soldered the connections - it would probably work better/be cleaner/tidier.
THINGS I HEARD:
Internet seems to think aftermarket exhaust will melt your stock indicators with a tidy. This particular tidy, I am glad to say, does NOT place the indicator in the path of my Remus exhaust.... so if you're the other guy with a Duke that bought the Remus slip-on, everything is fine. Everyone else, you're probably fine.
Other than a couple of caveats - the kit really is pretty nice. My last tail tidy kit was like 3 bent pieces of 22 gauge steel so this thing is kissy.
9/10 a point deducted for the weird wiring issue and a inner disappointment that the brake light isn't quite as nice, but no points deducted.