Hi Alyson,
If I were you I would order the 1897 cert through a NSW Transcription Agent and mention in an email etc that there was an amendment in 1913..
((Include the NSW BDM registration eg. 14011/1913 REILLY ARTHUR D DAVID H MARY ANNANDALE in your email ))

BOTH certs should actually be kept together although I'm not sure whether they will charge you twice or whether they will be able to access it easily.
The NSW Transcription Agent will be able to offer you more advice.

Kellie