Something you said caught my eye - you say she also called it "stucco fish".
I've never heard an Italian call "baccala" by this name, which makes me think
that the fish she cooked might have been "stalk", hence "stucco", another type
of salted fish which is very "stinky" when you first buy it and soak it. It
that's the case, you might have a better chance of finding what you're looking
for. What do you think? Is this possible?