To deploy node files on production sites or not?

There are two approaches. Neither involve committing node modules or bower components because it adds a lot of useless overhead in the git history and isn't necessary.

• Your committed aggregate CSS per gulp should have everything in the bower components
• Your committed aggregate JS per gulp should also have everything in it that it needs

So then:

• There is only a need to commit package.json in your theme, anyone can run and get the packages, and/or
• You may have a build server like Jenkins fetch and compile assets and push them out

If your live server(s) recompile CSS with extra jobs, I would advise installing bower/npm there and running the appropriate commands when you need them.

Closing. In summation.. do not commit node/bower files. Best practice is to have build tasks build/bundle assets up via Gulp into as few files as needed (css/js) and commit that into the project.