The way people describe a certain kind of architecture can change a lot with time and place.
For example, and to answer your question: Gothic architecture started in the 12th century, and thanks to its very innovative characteristics at the time (structural and ornamental) was given a proper name Opus Francigenum (Latin for "French Art"). But the word "Gothic" was only first used to describe it in Italy in 1518 by the painter Raphael. Le Robert dictionary says it is used this way by French scholars only a century later in the beginning of the 17th century and gradually took over.
So your 17th century architect might have called Notre-Dame de Paris opus francigenum or gothic, depending on how up to date (or Italian) he was ;-).
As for Baroque architecture, Wölfflin (1888) is indeed regarded as the first who applied the term for the architecture after the Renaissance. Previously (but only from the 18th century on) people rather called it classical, as modern masters began to be regarded as as "perfect" as roman and Greek ones.
Interestingly, in French, people still describe most of the architecture of 17th-18th century France (such as Versailles) as classical (« architecture classique ») and not Baroque, which kept its pejorative connotation. In English and German, you use Baroque for the same buildings.