No worries, you have a genuine Mobius with a very slightly modified case design. The new light pipe makes it much easier to see the different LEDs and, IMO, gives the case a more professional look. It's also better in keeping out dust from the camera's innards. The new case is otherwise identical to the old case except you may find the buttons stand a tiny bit higher than on your old case. This is most likely due to manufacturing tolerances. I don't think it was intentional and it may not be the case on your model.
Although there have been a good number of different board revisions this is the first revision the case has undergone, not counting the very early cases without the rear LED and the slightly different heat sinks that have been used in the past.
The boards are only manufactured in small batches which makes it easier to add hardware enhancements based on returned boards or user experience. A typical example of user experience is better component placement which makes it easier to swap the lens module.