If they don't have the orange tip, it is always best to treat them as if they are real; mags out, cased, and in the trunk. That said, a lot of guys bring their guns in tote bins, bags, boxes, loadout bags, ect., and never have a problem. It would probably really come down to the police officer that pulled you over and how well they understand the law, which is a fairly grey area.
I always error on the side of caution. I've had an officer stop me outside my apartment when I was carrying two gun cases and wearing camo. I just explained to him what I had, he fondled them a bit, said it looked fun, and I went on my merry way. Your mileage may vary.