Chuck,
With the introduction of the WEG Elite model, the Custom Imperial was downgraded to what used to be the WIA and WIB. The Imperial (WIG) name was downgraded to what used to be the Custom Deluxe (WCD) model (with a single kob for the 4 wash/rinse temperature selections, a separate speed knob and no 6 position fabric selector).
While the early 1970's 1-18 washers with a water level knob usually show a pictogram of an agitator next to the water level knob, the mid seventies models like the WIA and the WIB didn't show one. The later models did again.
And after 1976, even the TOL models didn't have 3 speeds. The Custom Imperial from 1977-78 was the WIC-A (it replaced the 1975 WCI and the similar 1976 WIC) and it still had the lighted panel, the 8 position fabric selector and the pre-wash/extended soak and extra rinse features but no 3 speed motor and no "Hand Washable" selection (it was replaced by a second "Delicate" position). The Elite which replaced the Custom Imperial also had only two speeds.