A quick question

[Fade]

Would two people with the same gnosis mark know that the other person had the same mark?

[John Vicari]

If a person bears a Gnosis Mark from a specific deity, they can instantly tell if someone else bears a mark (and how many) of that same deity, even if the mark is hidden by clothing or otherwise obscured. Positive or negative, it makes no difference.

Taken from http://www.mizahar.com/lore/Gnosis#Facts_about_Gnosis_Marks.