No you will be given one code not both.Since the job title Site Reliability Engineer is overlapped between 261313 - Software Engineer and 263111 - Computer Network and Systems Engineer. Which ANZSCO code will this role will be classified to or it can be either class?
Usually ACS will recommend something if they feel the code you chose to apply is not the one for you. If you end up not getting either of them and something from STSOL list, then you have to consider your non eligibility for 189 visa too.
Others can tell you better.