Just what is included in a factory dry weight number?

Well, maybe his trailer got shipped without the sticker. Oversights happen, and that's certainly not a reason to argue that there are not procedures and policies, and regulations pertaining to it, or that the trailer manufacturers are involved in some kind of back room deals with the dealers which is what this thread has evolved to over the course of five pages.
I'm not going to try to argue this or try to explain to the OP any more about this. Let him think what he wants to.