Hardened Valve Seats or Not?

I once had a valve job done to a 340 and didn't get hardened seats. In less than 10,000 miles the engine was running rough, and when I took the rocker arms off, some of the valve seats were so beat to ****... The #7 exhaust valve was sticking up 1/4" taller than the rest. And a few others were also, but not as bad as #7....

Now I always get hardened seats on the exhaust valves....