In the case of Wagner, Griswold, Favorite, and other name brands, small pieces like these were toys. The notion that they were salesman's samples is often repeated on eBay, but they were not produced as such. Unmarked pieces like the pot here must certainly be toys, as the workmanship doesn't appear to equal that which one would expect of a full size piece, so a salesman would not be likely to use it as a representation of his main wares. The best we can do with such pieces is to compare their characteristics to the designs and technology of real cookware from various era in order to approximate when they were made. But determining by whom and exactly when is unlikely.