If asked just lie. Lying to a superior is illegal but not when it comes to your religion. Sure it is illegal for them to harass you based on religion but they can find other ways of getting under your skin.
You may never find that regulation. So it all boils down to you deciding to remain covert or overt.
"I've learned . . . that life is like a roll of toilet paper. The closer it gets to the end, the faster it goes." ~Andy Rooney
"At last I shall have time to devote myself seriously and freely to the destruction of all my former opinions." ~Descartes
“The first principle is that you must not fool yourself—and you are the easiest person to fool.” ~Richard Feynman