I contacted Cam Simpson about this who has done a huge amount of work on the NMP and he sent me the following:-
Thanks for the J.W. Jones info. This is not George Jones (Number 148) who served in the AZW but John William Jones who enlisted at Pietermaritzburg on 26 April 1874 and was allocated Number 38 so he was an original. He purchased his discharge on 20 March 1876. J.W.G. no doubt was one of many of bad character in the original members of the NMP that were recruited in Natal. Dartnell, quickly started recruiting through the Natal Agent in London to obtain men of better character.