It looks that it is hard to “break” the skeptics!
This step can be performed by each himself, but – if it is easier to be skeptical than give 5 minutes for research – let it be. It is not hard for me!
Step 1. Open, for example, eparts.lv; enter the OEM code: 12120040551

- enter each of the alternative codes in Google; choose the image search.
Champion:

Bosch:

NGK:

I don’t know about you, but I see the “simple” side electrode.
And in this image – here, how the used BMW NGK spark plugs looks like:

Do you see this very tiny “bump” on the side electrode?