I was wondering the same thing, at least the more recent Specimen notes. The 1937 Specimen notes have the missing signatures, the punched holes as well as multiple red ink and perforated "SPECIMEN" stamps. By contrast, the Bird Specimen notes only have 3 red ink "SPECIMEN" stamps and the control number. I don't know how many non-collecting people would notice if they were given a Bird $50 specimen note from a bank machine.
Anyone know if and when the Journey Specimen notes will be available?