That sounds like a low price for a Clark Custom gun, although the finish may have a lot to do with that. The market doesn;t support "ugly" guns very well.
I have two guns that have been worked on by Clark, one they built from scratch. The Excellent Trigger is to be expected.
Find out if they built the gun, or just installed some aftermarket parts adn worked the trigger.
Chances are that this was a store bought gun, theat someone sent to Clark to "tweak".
Also, what kind of frame/slide is it? If the gun is a Norinco, he might even be asking too much, but if it is a Caspian Damascus it might be stolen! Consider the original price of the bare-bones components.
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-Essayons