If you blow through the hole in the back, on the original boxes..(pre-click lock lid)you will find that it does indeed connect, and create an air path that will blow vapor.
I have seen people fill entire bags using the "for production purpose only" hole....
I say it all the time, and people ALWAYS argue the point with me, and explain how the hole is for production only.
I will go ahead and call it an air hole regardless.. and here is my proof:
Well, the hole is for production. It's actually really easy to see how it works if you just look through the battery hole. The hole in question does pass through into the heating chamber, but it's occupied by a rod. This rod might not block the hole completely as shown in your video—or it might, as it does in mine of the same vintage (verified by my similar test). Given the nature of the way it's manufactured, I think it's safe to say that air flow through that hole varies from LB to LB. In any case, air flow is not its intended purpose, and the pushback ring in later LBs makes it even less likely that any air will flow that way at all.