Oops! Missed JensL post.
Now I'm confused

:.
Originally I thought that louvres are made from metal. Then there was a post somewhere that claimed they are plastic.
OK - for me it is hard to determine because of the layer of black soft paint covering the louvres. It is definitely not black anodised Al alloy finish. So if I tap it (gently) with fingernail, it doesn't have that typical metalic sound - it really sound more like hard plastic - but it could well be that layer of paint dampens it.
Not that it matters to me, plastic or metal , they look (and sound) good.
From memory, JensL has a personal contact with Beyer rep - maybe we can get some definitive answer here.