In real world we also have moonstone ...
Does that mean that anyone who wears it worship moon?

I mean ... this is classic A = B =/> B = A situation ...
Every shar worshipper will wear Onyx ...
Not anyone who wear Onyx is Shar worshipper.
Sure, there are other things like shape of that symbol on her forehead, paudrons, and on her armor in general. :-/
I still believe she should be using Discuise Self on her armor and reveal its true looks after she admits what she is.
So +1 i gues.

Even tho i dont agree with premise, the outcome would be welcomed.