There's no R6A on the side streets... (see full comment on "Look up your block")
In fact, R6A is proposed on 41st and 40th Streets (5/6) closer to 5th. and it was confirmed with the Brooklyn Office of the Dept. of City Planning
Link to the map- http://www.nyc.gov/html/dcp/html/sunset_park/sunset3.shtml
and you'll see that R6A has also been proposed for:
58th, 60th, 63rd and 64th Streets (3rd /4th Ave) and 61st St. (4/5 Ave)
GUESS THE ALARM IS ON! We await Anonymous' response...