Probably it would be good have this entered on the bower package for future releases:
At the bower.json file add the following:
"main": ["dist/compatibility.js", "dist/pdf.js"],
"description": "Bower build for mozilla/pdf.js.",
"moduleType": [
"node"
],
The "main:" property tells bower where to find the "dist" for the lib. Many json files for other libs specify that, and the Grunt script for Yeoman is no exception.
cheers!