Anybody knows if you can buy only the black, plastic insert that screws into the wheel (and is connected to the cap)?

Online I only see complete sets (of 4, some times also 1), that included the plastic cap with MB logo and the metal cover plate, like here:
https://ed-parts.com/product/amg-hub...mercedes-benz/
and here: https://www.kunzmann.de/shop/en/tire...rged-wheel.htm
That seems very expensive, also if I manage to buy only one, since I only need the black plastic insert for mounting the rest to the wheel.

Any thoughts about this?

 

I have the same question. Pricing on the whole unit seems crazy.