would I be foolish to trade barrels for a smooth bore 21" barrel with rifled sights on it? I have rifles for dear hunting but another friend said hang on to the barrel because they are hard to find.
Not foolish but I would agree with your friend about hanging on to it, at least for a time. Your rifled barrel is worth more than a smooth bore. Take your time and look for a used barrel. You did not mention the model number so I'm assuming that after market barrels are available. ....
Be Safe !!!