Fusilier in the Prussian/Austrian army at the time was a private rank given to light infantrymen. If you are a Grenadier Regiment the appropriate private rank will be Grenadier, if you are a Rifles Regiment the appropriate rank will be Jaeger, if you are an Infantry Regiment which the 8. Leib is, the appropriate rank for private is Musketeer. Just some historical backgrounds in case you were interested.