While building a Pathfinder Pistolero-archetype Gunslinger, I encountered an issue where Pistolero does not receive Pistol Training in the (Gun Frequency) Guns Are Everywhere! setting. The Gunsmithing feat is removed, however the archetype does not receive the class feature replacement.
I have tested this using a non-archetype Gunslinger class and it is still completely functional without the changes.
PCGen for Windows
Well, the archetype replaces Gun Training with Pistol Training. The Class feature replacement would be for the wrong feature.