Yes they do.

..."all of which are big names in the OEM supplier lists."

 

but I repeat

are these parts badged BMW with a BMW part stamp on them?

 

Probably not, no, as that will be exclusive to BMW AG and some parts will nt have a stamp on them in any case.

However, that does not mean they are not OEM parts.

 

I have bought dozens of parts for my car - mechanical and trim

And without exception they are badged and stamped

I accept some parts might not be so marked, but I have yet to see one...

The absence of manufacturer markings puts too many questions and doubts in my mind

But each to their own

 

The side trim that I bought from a BMW main dealer last month was unmarked.

It came in a BMW box though, which made it worth £70.

 

15 minutes work for you

don't be a tightwad

 

probably.

Perhaps <10.

You get what you pay for