Yes he is! His name is given as William Hermann (yes, William, not Wilhelm). He was a Gefreiter (Lance Corporal) in the 1st Hanseatic Infantry Regiment Nr. 75. This regiment was garrisoned in Bremen, Hamburg and Stade in 1871. Does this fit with the information you have?
According to the regimental history of IR 75 he was in the 4th company of the 1st battalion. He is not listed as having been wounded (good news for him!).