How to identify build number of a macOS installer? Today I read: 


  Apple today released an updated golden master (GM) version of macOS Sierra to developers… The new GM seed is build 16A323, while the build released last week was 16A320. 


After downloading, in the Finder > Get Info of ‘Install macOS Sierra.app’ I see ‘Version: 12.0.49’ but no build number.

How to identifier the build number of a macOS installer? 

My goal is to verify what installer I may be using.
The most reliable way of telling the build number is to check the SystemVersion.plist file inside the installer's OS image file (and not the build number of the installer app itself).


Mount /Applications/Install macOS Sierra.app/Contents/SharedSupport/InstallESD.dmg
Mount /Volumes/OS X Install ESD/BaseSystem.dmg (hidden file)
Open /Volumes/OS X Base System/System/Library/CoreServices/SystemVersion.plist and examine the build number under &lt;key&gt;ProductBuildVersion&lt;/key&gt;