Maybe in some small towns where people know police officers by their first name it isn't an issue, but in most areas if you call the police and say you might be in possession of stolen property you are just opening yourself up to being the target of an investigation. They'll want to know why you have stolen property, who did you buy it from, they'll want to check all your other guns to see if they're stolen as well, are you involved in other illegal activities, why won't you let them search your house? Police follow leads as far as they can.