I was referencing a direct quote from the author, looks like the Booker Prize board actually looked into it and disputes the certainty of the claim. Oh well. However:
1. Regime change doesn't happen instantaneously. The Francoist line of thinking was still pervasive after Franco died, and through the 70s there was a waxing and waning of censorship.
2. The book was still restricted in multiple states, the spirit of my comment still stands.
Regarding 1, I still don't see why what happened the decade before the book was published in another country has any bearing on whether the book was banned in Portugal.