Playhistory.dat timestamp

Hello, I am trying to decode the playhistory.dat (00010022) file, after reviewing information such as PTM_Services on 3dbrew, and editing-activity-log-on-emunand.388212 here on gbatemp, I am at a loss how the 4 byte value actually equates to a timestamp. Tried seconds/milliseconds since epoch (linux, 1970/1/1, 3ds 2001/1/1) but the values are erroneous. Has anyone ever been able to decode the timestamp values in playhistory.dat successfully?