Question about helpers and Iron:router

Quick question - just started working on a new project with a company that had an existing Meteor App. The app was originally outsourced to India. I’m trying to clean up some of the code. They have a layout template with a ton of helpers not in the layout.html. They are using Iron:router. Do helpers in the layout.js file propagate to whatever is the {{> yield}}? In either case it needs to corrected, but I wanted to know if it’s broken right now as is.