I would check however whether this part is plastic.
Is it painted metal?
I think it's an "L" shape that wraps around the drop glass as a seal. It fits into the seal which has a metal insert. Bend this out of shape and it'll never look the same again!
Yes. I reckon they are painted metal but they may be a bit encapsulated in the seal. Looks like an ideal wrap. The surface may be too flat to gloss finish. I'm sure the Alfa studio would have tried it out by now.