Spray paint them silver. If you can find them, they're going to be flouro-orange or transparent green, even if they are realistic gun shaped.
I wrote here once before: Seven years or so ago, we taped some Animaniac episodes. One episode was set during the Revolutionary War. On the deck of the Boston Tea Party ship, Elmer Fudd walks by and reports "Be verwe verwe quiet! We are hunting Wedcoats! Huuuhhhhhhhh!"
Well, if you just caught it quick, you would see himn carrying what looks like an old-fashioned blunderbus. But if you freeze frame, you can see it is a flipping bell held upright. Now this means that the producer (Spielburg) is so offended by the sight of a gun in his work,even when it is historically accurate to the time, that he has to delete it...but more than that, he has to indulge in a kind of lie to make grumpy old Wepublicans like me think we saw a gun. PC Lie upon PC Lie!