Nothing wrong with trying to get him to come down a little, but while you are trying to save a few bucks it could get away. I would try to get him down a little, but if I really wanted it I would pay the asking prioce before I would walk away.
In that condition, and with those features that is a steal compared to what a new one with similar features would cost. A new wingmaster is $650, they do not offer real parkerizing any more, and if it has been shot as little as they say it is still basically new.