Sometimes Park Slope building research comes into our hands via circuitous paths.
Today, while working our "Outside" shift at the Park Slope Food Coop, we accompanied a shopper and her groceries to her car so that we could return the cart to the store. She happened to mention that she lived in 12th Street, so we asked where, and it turned out she lives between 7th & 8th in a building with an 'A' in the cornice:
She said most people assume that the 'A' is for Ansonia, since the former clock factory is directly across 12th Street. On the contrary, she said that the 'A' is for "Acme Adhesives," a firm that formerly occupied the building before it was converted into apartments around 1980. Her understanding is that the building was erected in 1910 and that it might also have served as a garage at some point.