Steffano ?

     My 2nd great-grandfather arrived in the United States in the late 1800's.  Where did he come from?  I thought I knew...  What year did he arrive?  I do not know.
     The U.S. Federal Censuses from 1910 and 1920, as well as the 1915 and 1925 NY State Censuses show Stephen Duper's country of birth as Austria.  I thought he came from Croatia.  I'll have to re-read that letter from my grandmother's cousin.  I remember reading that he was from Dalmatia and had a thick accent.
     I have conflicting information as far as the year of arrival.  The 1910 U.S. census has questions regarding citizenship.  It asked for the yer of immigration and whether naturalized or alien.  The enumerator who covered the area left those questions blank.  The 1910 and 1920 censuses has year of birth as abt. 1873.  The 1915 and 1925 NY State Censuses just have his age which was listed as 43 (1915) and 51 (1925).  The 1915 census states that he was in this country for 25 years.  The 1925 census has him in this country for 35 years.  According to both of those censuses the arrival year would have been 1890 yet the 1920 census has an arrival year of 1888.  Stephen's death certificate from 1931 states that he was in this country for 44 years which would make the year of arrival 1887.  I have three different years of arrival for this man.  When did he arrive?  I have two different years for naturalization - 1894 according to the 1920 U.S. census and 1892 according to the 1925 NY state census.
     I had not found Stephen Duper's name on any ship passenger list until just recently.  Well, that is I think I found him.  There were quite a few Dupers who came from Austria but none of them were Stephen Duper with a year of birth as 1873 which was the yer I really thought he was born.
     The ship passenger list has Steffano Dupper born in 1872 and arriving in New York on 21 March 1889.  Could this be my great-great grandfather?