1) yes, anthracite dial has been discontinued
2) the dial is not made of anthracite but it does have a peculiar colour and looks different at every possible lighting and angle
3) not sure, but anthracite dials are very hard to imitate
4) i think the 220 has this feature but I am not 100% sure... I am more of a strap person
a few scans of the 91 and 86 just to share