1998 F150 V8 4.6L (165,000 miles)

My truck has a rattle in the Catalytic Converter (Not the pre-cat) when you hit it with your hand, or drive down the road. No codes are being produced. About a year ago I solved the misfire and P0420 Code problems and CEL flashing. So is the Catalytic Converter bad? After some research it seems that there is a consensus that the Catalytic Converter doesn't go bad. Is this true? The truck runs fine, but it sure seems to me the Catalytic Converter needs to be replaced. If I replace the Catalytic Converter should I also replace the Pre-Cat?