There have been quite a few reports of people getting that build in new devices or after a swap recently.
Sadly tho, no ota update yet. Google did release some new binaries a while ago for the devs, presumably those are present in JRO03R and JRO03S as well, but no official release of those has been pushed out.
If you really want you should be able to push the binaries to your device yourself, or get a rom that includes them, or just wait until the complete build is released.
But correct me if I'm wrong anybody, you will lose root if you update OTA. That's what used to happen in the past anyway. So in any case you'd probably be best off flashing manually.