Of course it is! You've probably figured this out by now, but if not you can just go to edit the script and change newval to anything you like. Just leave the matches[1] alone, as I believe this is the group for the regular expression match for the number of unread mails. The names[0] returns the Gmail name from the regular expression search. I edited mine to look like this:

newval = '(' + matches[1] + ') - ' + names[0] + ' Inbox';

You would want yours to look like this:

newval = matches[1] + ' unread';