Yes you are correct about the microfilm copies of old certificates in the SA Genealogy and Heraldry Society. I am not a member of the SA Genealogy Soc and they charge non members for use of their library.
However, these copies are also available in some Public Libraries. If you know the district the BDM happened then there is a relevant Public Library in that district that have these copies of certificates that can be viewed but not copied. Sometimes on microfilm and sometimes the original books.
In your case it is the District is Adelaide and the certificates can be located in the Unley Public Library on certain days only. This is a free service.If this is more convenient for you, you should give them a call because they have been renovating so not sure of any time changes.
There is no indication on the CD that I use as to what names are on the original certificates when they cross reference, so the certificate should be viewed.
Digger - South Australian Births 1842-1906 (c) SAGHS
Surname: HINCH Given Names: Samuel Date: 1856-10-23 Sex: M Father: Robert MCBURNEY Mother: Mary HINCH @ (nee) TORRENS Birth Place/Residence: Bowden District Code: Ade Symbol: X Book: 7 Page: 190 Cross Reference: See also: MCBURNEY Samuel Hinch