Thanks to manga_blue, we now know that they are part no. 965H-6050 (BUFF FINISHING) (manual wheels p/n 9965F-6050 (SILVER)).
This is the wheel:

However, while the finish is different, they appear to be quite different castings and not just a tarted up manual wheel.
Manual wheel

Auto wheel




Comparison of the wheel identifying marks on the reverse side

It is possible that those casting marks do not tell the full story. However it seems reasonable that Mazda chose a different supplier for the smaller quantities, and let Enkei get on with the volume production.