I recently found via Ancestry.com an entry for my third great grandfather, Gerson Heilbroner, in the 1862-1948 New York Index to Death Records. Heilbroner was mispelled Hhilbroner which was why I had not stumbled upon this before. This is definitely confirmed as my ggggrandfather as the entry mentioned his wife and daughter's name.
1. Would the dates of the index indicate that he died 1862 and after-not before?
2. Would there be a next step in finding his actual death certificate/death date? I surmise that he died before May of 1865 because of naming patterns in the family.