Courtesy of "Decorative Arts Study Center", what was apparently a well-regarded
educational non-profit that operated from the early 1980s until the mid-1990s.
Of course the marker is a form of a "credit to themselves," but in earnest: The visitor
to the Mission does not care about a specific "company" donating or not donating
anything. The visitor is interested in History, Spanish influence, historical
events and the pre-US architecture. To my eyes such plaques have no value.