I see lots of lugs advertised for sale as being either NOB or COB.
I've got a bunch of Slingerland lugs from the '50s and '60s and they are all either COPM or NOPM, that is to say Chrome over Pot Metal or Nickel over Pot Metal.
I think those not "trained in the metalurgical arts" mistake the nickel or copper that may be visible on the backside of the lugs for brass.
My guess is that some of the fairly ancient drums may actually have brass lugs. For example, it's hard to imagine the old lugs that did not have inserts being made from Zinc based Pot Metal.
Other than tube lugs, does anyone know if/when brass lugs were actually used?