no, it was not needed since you can edit the styles from the admin panel by default.
however, that is not a good way to edit the style files.
use your ftp, download the overall_header.html file to your computer.
use a real text editor to make your changes, upload back,
refresh the template in your admin panel/styles tab for your style.
then refresh your browser to see the changes.
if you do not like it, try again.
remember, you should always work from copies, that way you are never more than a couple of clicks away from complete recovery is you mess it up completely.
also remember, it is just a bulletin board. if you screw it up then it is no great loss and you can always fix it quickly and easily with new files.