Hey CoryB,
I work for the Feds also but in a land management agency.  They tend to be more tolerant toward beards but I still do not see many beards at my level and above.  Except a few emergency response positions and Department of Defense positions most Fed employees can grow any type of beard or have as long of hair as they wish.  There may be some Law Enforcement agencies that have restrictions on beards but I know our Law Enforcement can grow any beard they wish.  Take advantage of being a Fed.  It really frees you up in many ways as far as what you can legally wear for beards, hair, and even clothing.