2006 New York Code - Signs In Existing Buildings.

 
    § 27-396 Signs in existing buildings. (a) Signs installed prior to the
  enactment  of this article may be accepted by the commissioner, provided
  that such signs will adequately accomplish the intended purpose.
    (b) In  buildings  existing  prior  to  January  eighteenth,  nineteen
  hundred  seventy-three,  the commissioner may modify the requirements as
  to location of signs where compliance would cause  practical  difficulty
  or undue hardship.
    (c)  All existing buildings not already subject to the requirements of
  this article as of January eighteenth,  nineteen  hundred  seventy-three
  shall  comply with the requirements of this article on or before October
  first, nineteen hundred eighty-five.