2019 prius crossbar endcap key

Did you ever get a key? I have a 2017 and don't have the crossbar endcap key either. Can't seem to find this little part anywhere online, other that as part of the kit you mentioned.

 

I had the same problem, and tried for months with dealer to get replacement key. so I made my own. (1) find a screw driver with removable tip, and remove the tip. This would leave you with the handle, rod, and at the end, a hollow tube, (2) find a small plastic wire connector and press it into the hollow end of the screwdriver. about half or a third of it should still be sticking out. (3) with a candle or match or heatgun, heat up / soften the wire connector. (4) while hot and soft, press the connector firmly onto the key area of the rack and hold for 5 seconds.

The pattern on the inside of the wire connecter will now match that of the gears on the luggage rack, and you will now have a tool to turn the knob to unlock the car racks

 

I bought a used OEM roof rack but didn't come with the key, so I ended up drilling two small holes and used the tips of needle nose pliers to turn the lock, works well.

 

OK, I've been there. I bought the new package of four just to get the key and one end-cap. You may not believe this, but there are different keys - I guess to prevent theft. I didn't mind destroying what was left of the old end-cap to get that one off, but the key that came with the package of four new end-caps is a different number (IIRC they are numbered for the sizes) and a different size, and it only now fits the new ones I have.
Which raises a question as to - how many different keys are there?

This is also why they won't just sell you a key. You get the key made for your set and that's it.