This index most likely applies to the paper files at the US National Archives Washington DC. At the site www.archives.gov
select research our records, Archival Research Catalog, enter 559947 in the search box. It should bring up the catalog entry for the "Subject and Policy Files" of the Immigration and Naturalization Service. Click on the title "Subject and Policy Files" and then select print in the right top corner. Click on print full details and it will display a full description of these paper files. Scroll down the list and there is a file number for each box. Note that is says "The current box list covers only a part of this series. A full list will be provided when it is completed." It looks like the records on your person are in 53595/512. The catalog entry only goes through 53036/401. Email the US Archives and see what they charge to send you a copy of the records on your person.