The meaning behind two Gramercy lampposts

"Four Gramercy Park West, with its ornamented white doors and iron lace terrace, is about as breathtaking as a New York City townhouse can get (number four is at left). Built in 1846 soon after Gramercy Park was transformed from a swamp to an elite neighborhood, the Greek Revival home “features sun-filled rooms, high ceilings, and elaborate crown molding, and it comes with a coveted key to the park,” writes 6sqft. It also features two cast-iron lampposts flanking the front entrance on the sidewalk. Oddly, the mirror image townhouse next door, Three Gramercy Park West, has no lampposts. So what’s the significance? The lampposts are remnants of a mayoral tradition leftover from Dutch colonial days. ..."
Ephemeral New York