The Core Rulebook is both written for Pathfinder RPG and more recent than the Campaign Setting, which was written for 3.5.
Since the basic rule is that more recent material trumps older material, and that core books trump supplementary material, I would go for the Core Rulebook version.
Agreed - however if you were playing inside the campaign world then if the gm ruled for the campaign one the campaign one would stand. I would still go for the core rules as they are the core rules for a reason and are the basis of the game.
in the PF corebook there is a Curve Blade, Elven.
in the Campaign Setting there is another Curve Blade, Elven.
the PFSociety guide says that every weapon in the Campaign Setting is legal.
the question: wich weapon is the one for play¿?
Core, some where, some ONE, posted that the Core books override earlier stuff.