In the minor department they moved the USB-plug about 1mm further from the back, making it easier to use e.g. round magnetic charging plugs, so the lower half is not 100% identical. But we are talking a very small change, It could still be that the usb-board is the same, or at the least are physically exchangeable without the need of extending the hole,
Any changes in the antennas could be what is put on the same basic metal frame.
We would need to take one of each apart side by side, or have an official reply on which parts that are identical and which one that are just 'similar' bu