Late S3 wiper arms

[gjz30075]

I'm finding that the shiny wiper arms and blades on my S3 #7286 are really 'flashy annoying' on a bright day. I'm
not sure if it's chrome or polished stainless but I would like to switch to the brushed (ie, dull) finish like what is on my Sprint and found on S4 cars. Yes, I know the answer is 'just do it' but what is 'correct' for a late S3?

The arm is the 5mm type and I found the later (dull finish) arm is 7mm.