Valve Job performed on a /6

The 69 V100 had a valve job prior to me purchasing. Now..., is that indicative of running unleaded fuel in a system designed for leaded fuel? Some people think the whole recessed valve seating issue being related to unleaded fuel is a myth. Some people say you need hardened valve seats to run unleaded fuel in these types of motors. What is the real deal? Should I be using an additive? Everyone seems to have a different opinion on this.