Yes, the I.C. as dogma is recent, 1854. Dogma is what the writer was writing about.
As I've read/heard from several sources (to paraphrase), "The Immaculate Conception as dogma may have been declared officially in 1854, but you would have had a hard time finding a Catholic who didn't believe that dogma after Duns Scotus resolved the theological debate in the late medieval period." My St. Ephrem source proves that this belief has been around for a lot longer, and the intervention of the centuries has caused disputes to result.