Updated version number not showing
I had this exact same problem on my Moto G 2nd Gen 4G where after the update my Android version stayed on 5.0.2 and did not change to 5.1 like I expected. I contacted Motorola about the issue and they confirmed that Android 5.0.2 Lollipop is currently the latest version of Android for the Moto G 2nd Gen. They couldn't however explain why I had received a false OTA update and promised to raise the issue. So from what I can tell, the OTA update is most likely to be an error on Motorola's behalf but this should be fixed when Android 6.0 Marshmallow is released for the 2nd Gen Moto G.  

Hope this helps answer your question.