All I've ever owned are cars built before 1972 and trucks built before 1980. I've never used lead additives and have never had hardened seats installed on any engine when a valve job was required.
Unless you're auto-crossing your truck, you will never experience premature exhaust valve wear with standard valve seats.
The Bismarck has 200,000 miles on it running unleaded fuel only for more than 2/3rds of its life with absolutely no problems. I just filled it up today with unleaded. 15.6 mpg.
