Question re: Iowa / Nebraska Naturalization Records
My question is regarding the online Nebraska Naturalization Records 1855-1989 collection ( https://www.familysearch.org/search/collection/3241361 ). I have located index cards in this data set that provide certificate numbers for several ancestors (Klaas Versteeg, Conelus Koopmans, and Lukas Van Hees) who were naturalized in the 1860's, 1870's, and 1880's. The noted district and circuit courts are all located in Iowa, in the counties where these men resided. Is anyone familiar enough with this database and / or the naturalization process to know whether the entries in this index should lead to further records in Nebraska? Or do they just act as a finding aid for identifying the Iowa courts where the naturalization proceedings took place? Thank you very much for your assistance!