It seems that the "1/2" switch on the PCB chooses between which 4k (assumption it is connected to A12 of the EPROM), then the "load/save" switch chooses between the 2k within that 4k (assumption it is connected to A11 of the EPROM).
* The filenames written into the directory are there to indicate there is Disc Wizard data present. The filenames contain lower case characters so can't be run from BASIC - the files will not be found. The files are not correctly setup anyway, they lack the cluster values, extents and other data that correctly describe a true file.
* Dissassembly of the code indicates it uses direct FDC disc access for loading/saving.