They also look like they have slight curvature on the Seattle one - like the cover on 'covered buttons' from the old days, just perhaps hammered and flattened ever so slightly. Check this pic for reference, if you buy in - you can see what I'm seeing. With the curvature and how thin - I can't see this being machined:
Drill a hole in the middle and these pieces look thin enough, and would never be too heavy for your ear
Considering T-Jets, etc - it seems like something Wah would do with material at hand.