I'm curious about the US doctrine for anti-shipping attacks 25 years ago -
say, the late 70's/early 80's?

This topic is covered (fictionally of course) in Stephen Coonts novel "The
Intruders," which is set in the mid-70s. The protagonist is assigned to
study how best to attack a Soviet surface combatant (cruiser? destroyer?).
In the novel, no precision ordnance is available and the attack plan
requires flying into the evelope of both SAMs and AAA. When queried by his
skipper as to his conclusions, the protagonist says "I've become a big fan
of attack submarines lately."