Accompanying this name index is a booklet by archivist Jerzy Szumski, available at http://pbc.biaman.pl/dlibra/docmetadata?id=16898. Beginning on image 35, there are further details about the archival signatures referenced in the name index, such as dates. The date range is mostly 1883-1915.
There is also a separate place index available at http://pbc.biaman.pl/dlibra/docmetadata?id=16901.
-Logan