Regarding removal of AR coating-- I just received a 45mm UPO with AR coating that looked to only cover about 60% of the crystal.
I may send it in for a re-do at some point in the future, but right now I just want the AR stripped.
Having read here to not clean your AR coated crystal with acetone, I tried using acetone to dissolve the coating.
It went well. I work in a laboratory, so I have access to acetone, Kimwipes, and a fume hood. Those make this a bit easier.
I soaked a Kimwipe, and buffed the crystal for about 10-15 minutes. All the AR is gone now.
Acetone is not abrasive, like jeweler's rouge, so I could do it with the crystal installed, yet not worry about scratching the bezel.
It does not seem to have affected the black of the bezel.
I recommend this method.