I used the term 'blank' really to exaggerate the difference between the two bowls. It is more than likely that the uncut piece is/was the norm and the the cut one unusual (Oooo, I just realised, I would say that wouldn't I ??).
You're right it does look futuristic for the time, but there are other pieces that would sit well with it from that period by W/F's - for instance, see plate 118 on page 126 of Lesley Jackson.