If a tablespace has 2 files, is the foll backup methodology valid?

alter tablespace APPUSER begin backup;
host copy G:\APPUSER01.DBF F:\backup;
alter tablespace APPUSER end backup;

alter tablespace APPUSER begin backup;
host copy G:\APPUSER02.DBF F:\backup;
alter tablespace APPUSER end backup;

Or should we always back it up as

alter tablespace APPUSER begin backup;
host copy G:\APPUSER01.DBF F:\backup;
host copy G:\APPUSER02.DBF F:\backup;
alter tablespace APPUSER end backup;