If you look carefully you'll see the circled item is a video camera with an attached microphone. The microphone does look like the barrel of a firearm, however, the make and model of the camera were verified here shortly after the event.
There may indeed be other images of other firearms in St. Louis. This image, however, is of a Boya microphone attached to a video camera.
>That's kind of what this place is all about.
That's exactly right. There is a lot of distributed knowledge and expertise here. Sometimes the breads just fly by and issues get revisited. I have a great deal of respect for the accumulated wisdom of anons.