Old news, dredged up by writers who don't mind ignoring linear time progression in order to make a better headline. It is possible that sales of this existing product could have increased after the recent zombie news, but the article does not claim to know that.
IMO, these are a waste anyway because the best zombie gun is a 22 LR or maybe 22 mag, hopefully with a silencer. Anything but a direct brain shot is wasted, and a 22 is good enough for that. Larger calibers are unnecessary, will attract more zombies with their louder blast, and waste 2-3 times as much space/weight in your travel pack. And if you are unfortunate enough to be facing more than one zombie at once, the lighter recoil of a 22 will make it easier to re-establish your site picture for the next crucial shot