You are correct.  I moved into my first apartment in college Fall, 1974.  A brand new complex down the street built that winter/spring/summer had Hotpoint kitchens with this same dishwasher.  Compared to my late 1960s Hotpoint in my apartment, these were great cleaners.  Had a much longer wsh phase.  Still reversing motor.  And there was a suds kill or drain/debris flush at the end of wash/beginning of rinse that fascinated me too. 

Would you believe my mid-to-late 1960s was even noisier?  At least this one in the ad had a somewhat soothing droan while it washed and rinsed.  Draining was noisy.