How old is the Stevens Favorite?

The first model Favorite has a side plate and dates to the 1880's. The second model, late 80's/early 90's, has a one-piece action and a nice little flowing s-line atop the breech block. The action is less than a inch thick. The third major change was the 1915 model. It has a little thicker action and the breech block is plain. There are many minor variations of extractor, ejector and pins. Of course, some Favorites are quite modern. To be exact, we need to know which Favorite. For the avid collector, it will ever after be the "Age of the Favorite".