Only way to tell if it is the battery is to change it IF it can be changed.
Let one of your techies loose on it as it could be a sign of other problems.
A big deal? If you feel like resetting the clock and all of your settings every time you boot up the PC I guess it isn't a big deal. Not my idea of fun, though. If the battery does die completely, it can end up meaning that your system will not start at all. I would say that was a big deal.