Hi, I was able to choose the colour of my key versions when I ordered my item. There were four versions in terms of the keystroke types. Since I chose blue, I think I got the blue keys. But I can't say conclusively how this should actually be presented.

No, you can't. Surprisingly, we got additional blue keycaps with MX-Speed-Silver. With MX-Speed-Red, it was a different colour, because we bought blue ones.