Heroku rails app not serving font assets

Trying to serve fonts from a deployed Rails 3.2 app that works in development. Example url:

http://ift.tt/1K8dZt2

(located in app/assets/fonts/146726/)

Results in 404.

I recently added:

Application.rb:

config.assets.paths << Rails.root.join("app", "assets", "fonts")

Production.rb:

config.serve_static_assets = true

FWIW the location does not have to be /assets, but what is needed to get heroku serving those font files?

This is a requirement by the typography.com set up (http://ift.tt/1K8dZt6)

Edit I have just found out that the .eot files are being served, its just the .css files that are not. Suggests something in the asset pipeline that I don't know about?