This page talks about having a custom html button that prints when clicked. In the javaScript, before it prints some code runs to show the names of the sections. The same way you are talking about above in your post.

Custom HTML:

<input id="printer" value="Print this page" type="button">

javaScript:

$('#printer').click(function() {
  $('.sections, .Submit').show();//or whatever code you need to show the section labels
  window.print();
});

I am not positive on exactly what code you need to show a hidden section header, but this code should work for running whatever you need to do before it actually prints.

Hope this helps :)

Chris