Nick -
That is a 1980 model 70-series. There were two with this panel, the 20721 which has the 1981 and older largest tub (25 gallons or so) or the 20741, which was the first of the "energy efficient belt-drives" as I'm told Whirlpool called them, with the 22-gallon tub. I remember the 20741 on the sales floor with the new 1981 models with their revised panel graphics. Apparently for some reason Sears wanted one model of the old panel style for a while.
This is a dandy machine - five levels, five temps, two speed, and it has a "real" self cleaning (tub mounted) lint filter. The 20741 added two non-electric dispensers.
Both models were very popular. The 20721 was my Mom's choice for washer number three before I repaired our 1974 machine in Feb. 1981 and we cancelled it.
Good luck getting this machine, it looks nicely kept.