Guns without names clearly marked are often incorrectly called Guild guns. They were most often made for "the trade" to be marketed by someone else, sometimes large retail firms and sometimes individual shops. They are sometimes marked by the seller; in which case they may be incorrectly said to have been made by the seller. Other times they were/are sold without being marked; these are the ones incorrectly called Guild guns. Sometimes, even though not clearly marked they may display a logo or some other mark, inside, identifying the actual maker.
Mike