Ding! Ding! Ding! We have an answer to our reader's question on the red licorice from the '70s. Here, direct from the Red Vines licorice site, is the explanation:
Introduced in the 1960s, Family Mix assorted candies is a collection of our most popular bites consisting of red and black candies. Replacing the original product mix of Whips, Red-Ets and Lic-Ris-Ets (ALC's first line of licorice candy), each bag now contains Original Red TwistsT, Black Licorice TwistsT, Red Vine Whips, Super Ropes® and Licorice Ropes® candies.
Many, many thanks to Philly for answering this mystery!