I don't know where u get ur numbers from, ksg's on gun broker sell for 1600-1800 so 2800 is high I agree, but no different than someone asking $600 for a used glock
It's no different than people trying to sell an OD glock 19 for $750-$800.. A used glock is a used glock, 275-300 so in all reality there is nothing wrong with asking that for a ksg. At least his gun is NIB