That is discerning, but in 30+ years of looking for a 340 for my car I have always looked at whatever I found with the knowledge that I will have to tear it down and rebuild it regardless of what the seller says. I don't care if it's presented as a $4000 freshly rebuilt motor-I want to know what's in there before I go through the trouble of putting it in my car.
The beauty of the one I finally bagged is a reputable machine shop did their thing and I assembled it myself. I'm 100% confident in my work.