There are only three Oates listed on the Medal Roll.
There is Charles, George and Joseph.
Looking at the address in the 1939 records, we find Mr Oates and his first name is Albert so he is not listed on the Medal Roll.
As the Egyptian war is mentioned first and then the Zulu War, in my option he took part in some other African War and not the Zulu War of 1879. So I would say he did not take part in the Anglo-Zulu War of 1879. Very happy to be corrected.