Yes, it is a "more modern" version of New York State Seal button. Yours dates from the late-1800s into the early 1900s. It is shown as button NY-31A in the book "Record of American Uniform And Historical Buttons" by Alphaeus H. Albert. Mr. Albert mentions that the "later" NY State Seal buttons are known to have been (and still are being) used by Municipal (town & city) employees rather than military forces. In the early-1900s, all the State Militia units became National Guard units and quit using their state buttons, being replaced by US Army buttons.