Hi, Respo,
That is a prototype based on a special process which makes stainless steel harder than sapphire, but alas, proved not commercially viable during evaluation.
The bracelet, done at the same time, used ADLC from the time (4 years ago) - the bracelet is showing wearaway, as all DLC / PVD / ADLC will, at some point; the head is as "perfect" as the day it finished the process.
Shows an interesting real world wear characteristic comparison...Alas, sometimes, the best solution is not a commercially viable one...
All done with the knowledge and support of AP, of course.
I mention this because I know it is becoming increasingly popular to DLC or PVD your own steel watches (AP, Rolex, et al) - sure, go ahead, DIY (Do It Yourself) but don't whine when the coating starts to wear off 1, 3, 5 years down the line, at which point all you can do is throw the watch away. AP won't refinish it for you (as they will with AP produced PVD models like the La Boutique NYC or End of Days)
So do NOT take the existence of this watch as encouragement to try it yourself! Do so at your own risk!
Yes, that's an original AP dial, flange ring...custom made and fit for this prototype.
"Triple Orange"

Cheers,
TM
"The secret to success in life
is to keep believing in the possible,
but to focus your energies on the probable."