MapPLUTO's footprints aren't for the buildings, but rather the boundaries of the property. It's a big shapefile for each borough. Totally worth exploring. It's got an insanely detailed metadata breakdown that explains a ton of the eccentricities.
As for the dates, most are guesses. If you plot the dates, you see they're overwhelmingly years that end in 0.
As for the dates, most are guesses. If you plot the dates, you see they're overwhelmingly years that end in 0.