Possible to detect if an installation is a preview build?

I want to detect programmatically, from my build scripts, if a particular engine installation (Launcher as well as Github) is a preview release. The Build.version file would seem to be the place, but from looking at it I can’t see a clear way of differentiating a preview release from the first proper version (both will have patch number of 0). Anyone have any ideas?

Maybe BRANCH_NAME macro helps with what you need; check it out in Engine\Source\Runtime\Launch\Resources\Version.h

Thanks for the feedback guys. Unfortunately, as far as I can tell at least, none of the information in either case differentiates specifically between Preview and Release. It seems the only change in information from Preview to Release is just increased build/changelist numbers, just as when changing from one preview to the next. So there seems to be no way to detect the transition from final preview to initial release.