I have to agree, especially if the engine (or head) has some old miles on it. I have read in some resto books that a valve seat with alot of leaded miles on it will have enough residual lead on or in the seats to keep the engine going. A new head, however should probably have hardened seats put in at some point.

Current fleet (subject to change w/o notice)
\'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run.
My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787.

Knowledge is a wonderful thing, but ignorance means you don't know you can't do something.