hardened valve seats or not

Yes, it should have hardened seats in it.
Even if it didn't you can run unleaded gas in it until the valves need to be ground because all the seats used to be surface hardened. Once the seats are ground they lose that so it is best to replace with hardened seats.

You can always add lead additive if you are uncomfortable running unleaded gas. I have also heard that hardened or not doesn't make a difference