[Ken Maltby]

If you are only using KOReader for PDFs, then you might want to create a .PDFs folder. It is mostly a matter of the issue that processing a number of documents into the Kobo database can become a problem if there are a large number of them or if they are in formats that the stock readers don't handle or if they fail to meet Kobo's standards (Perhaps all those bought from the Kobo Store, will pass?) You could just let Kobo process them all if you wish, for some that seems to work out with few problems. Your mileage may vary.

Yes, those instructions should apply to your device.

Luck;
Ken