I don't understand why it matters if you install the final 10.11.3 if you're just going to install the 10.11.4 beta immediately. The OS you would have is build 15E27e, and what was there before isn't relevant as the files for 15E27e are what's on your disk. It doesn't matter that you had the 10.11.3 beta on there before.Well suppose I installed build 15D13b and then 15E27e. How then do you suppose I install 15D21? I bet you can't.
Maybe I'm misunderstanding what you're actually trying to do.