Sure. In the main application.html.erb of your site, you should see this line somewhere in the <head>:
If you don't, then that's because you moved it into a partial (called rails_defaults, maybe -- that's what I recall from your first post).
//= require tree .
A generic (rails new ...) generated site will have all of this done for you, so I recommend you try building a new stunt site from scratch and see what gets built for you. Try building a new app, then inside that, using the scaffold generator to make a couple or more models:
rails new test_blog
rails g scaffold Post title body:text slug
rails g scaffold Author name email
rails g migration add_author_to_posts author:references
navigate to http://localhost:3000/posts
Everything you see will be run through the asset pipeline, although the full concatenation will not be there in development mode.
To see how this would work in production, you would first run:
rake db:create RAILS_ENV=production
rake db:migrate RAILS_ENV=production
rake assets:precompile RAILS_EN=production
and then when you started the dev server with the production version:
rails s production -p 3000
you would see all of the JS and CSS concatenated into application.js and application.css respectively. None of the individual files would appear at all. The whole thing will be minified and concatenated.