not brass on the metal inserts unless it's hidden .... their products are good because they make things exactly as factory, and they have a "library" of original rubber to work from, one of the best resources vintage vehicle nuts have
I got a set of mint dealer take-off TF panel barn doors that still had the original rubber seals, could have used them, but I asked Steele if they'd repro the seals if I sent them in -
they did, 100% perfect copy, and they asked if they could keep those originals for their "files"
Bill