As you were walking around for 30 minutes, the "new" guy was probably looking for someone to tell him what to do with a gun he had never seen anything like before. The regular dept. manager may or may not have even been there to ask, so he may have been talking to people equally un-experienced with the level of gun you brought in. Instead of dropping 1000's of dollars on a gun they had no idea about, which in their mind if they are wrong about could very well get them fired, his best answer was to tell you they just don't buy damascus barreled guns.
So instead of worrying about potentially getting his ass chewed out by store management, the guy making about $8 an hours came up with the answer he gave you. Of course not the right answer, but one which carried little risk for someone who is new on the job and is probably hoping he won't be working there for long to begin with. Maybe he'll learn more about vintage guns in the future and be able to help you, but more likely he'll move on to bigger and better things, which is the case with most people making minimum wage. I'm not sure why anyone would be surprised with the situation you found yourself in.
I took the gun there looking for an offer due to their famously unqualified experts.
What a bunch of unethical dumbasses.
So if I understand your first statement, you were intentionally going there to find some in-experienced person in the hopes of him giving you a ridiculously high offer on a gun they didn't know anything about. I'm not sure if your second statement is referring to the minimum wage worker you corresponded with, or with yourself.