Has there ever been a time when the Tomb of the Unknown Soldier was not guarded?

Has there ever been a time when the Tomb of the Unknown Soldier was not guarded? Since April 6, 1948, the Tomb of the Unknown Soldier has been guarded 24 hours a day, 365 days a year with zero exception.

Since April 6, 1948, the Tomb of the Unknown Soldier has been guarded 24 hours a day, 365 days a year with zero exception.