The 747 Classic is similar to the 777. Min or Med Autobrakes (as selected) are applied at main gear touchdown (via tilt switches that indicate the entire truck is on the ground). If Max Autobrakes are selected (VERY rare), Med are applied until the nose wheel WOW switch is activated.
Autobrakes are used routinely, so brakes are applied before nosewheel touchdown about 95%of the time.