Malcolm,
I was about to guess that those are mid-70s models, based on the graphics of the "program" settings, then I noticed the sale date note at the top of the ad. The plastic panels began in the U.S. in 1972 models and were eventually available as BOL machines, up to most 60-series models. There was even one 1976 "alphabet" washer as they're referred to here. The plastic panels lasted in one form or another until a few years ago in DD form.
There are some pretty interesting differences between the Canadian Kenmores and the U.S. counterparts, and I have never seen those centerdial plastic panels here. Very interesting, thanks for sharing!
Gordon