I am sorry NH, but I don't see the black finish. Maybe my old eyes aren't working and that is why. Anyway, the NS Meyer backmark was used from 1906-2000. This button would date between 1910 and 2000 because of the rim added in 1910. If it does have a black finish it would date between 1910 and 1923.
I can see the black on that one. Maybe the OP can tell us if there are traces of black finish on the button. Looking at the back I could see where there might be some around the edge but it seems odd that there is none in the depressed lettering.