Good luck with it. I'm not sue happy, but in this case I would strongly consider it.
Was Gamestop an inside store? Reason being, anchor stores with their own entrances and inner stores seem to be viewed differently under the general guidelines for the mall. The anchor stores seem to make their own rules in regards to handguns. The inner stores fall squarely under the mall policy. And yes, I understand it was not posted. Not even questioning that one. They rarely come right out and do that.
One of the reasons I rarely, and as little as possible go to the mall.