It doesn't give much detail - basically that he was naturalized in the County Court in Kings Co., was a citizen of Great Britain & Ireland, and his witness was Thomas M. Nolan, but 17 Oct. 1889 was listed his date of naturalization. I'm not positive about how it worked in that time frame, but I think the naturalization process generally took years, so likely this would have been well before your man was eligible for naturalization.