As I recall, Whirlpool / Kenmore standard-capacity belt-drives were said to be 14 lbs in the 1970s, maybe 1960s, and forward. Super-capacity debuted in the mid 1960s was "up to" 18 lbs.
Capacity nowadays, at whatever point in time that began, is rarely if ever stated in pounds. Cubic feet is the reference, which eliminates the need to validate any poundage claims.