Actually, your question is even more complicated. There are a finite number of sources for most of the components of guns. To some degree, this is true right down to the raw materials. Evidence that the lines of a particular continental action are close to those whose source isn't actually known can probably be found. I'm not certain that the best answers don't come down to the expertise of the work performed on the raw materials though. This is what I think was being put out for discussion above. Whether or not premises are open to the public rests on many aspects including insurance liability so I wouldn't necessarily read too much there. I also think that a review of comments and writings would reveal an ebb and flow for this even in the premier houses.