So I'm speculating a bit based on having been approached about these Pinkerton gigs before. I never got involved as even though the guys I would work with were legit, the licensing issues were sketchy at best. From initial impressions this is the goat show that ensues when you combine assclowns with poor business practices in the security field.
I would bet good money that Pinkerton in no way shape or form had anything to do with training and equipment. They find a sub-contractor who then finds someone to work these kinds of details. It honestly would surprise me if this guy and the subcontractor have their licensing in order to do armed security. Whether or not any kind of "training" was actually done is also suspect.
ETA @TGS gave a much better description of how this stuff works/ is supposed to work. My experience is that alot of these gigs end up filled with a body, any body, because the position needs to be filled right now.