I have a new 870 Police, bought on 10/31/18. Serial # starts with CC. It looks to me to have a plastic trigger guard, magnet won't stick to it. I thought all police 870s were supposed to have a metal guard? Thanks

I have not seen either one specified. I think plastic is probably tougher.

Trigger guards were either aluminum or plastic so magnet test wont work. If you arent sure if its plastic then its almost certainly aluminum. The plastic is hard to mistake for anything but plastic.