Larry:

Yes, you can restore to the original Factory data, styles, etc...simply download from the Korg Web site the Musical resources for the model you want to restore and is done.

As a suggestion, I always make sure I download in my Mac/PC the current OS, Musical resources, etc. for the models I use.
Also a good TIP, if you are a traveling musician (long distances or even overseas), like I told my Croatian friend, email to yourself your Backups, sets, etc. that way, if you loose your USB drives, SD cards,etc, you always can download them wherever you are, this actually prove to be a performance saver many times.

IMPORTANT NOTE, make sure you ALWAYS restore from the Model you have, meaning PA500 to PA500, NO PA500Musikant to PA500 even is the same platform, they have different internal maps, sounds, drum Keys, etc. Make sure it is like PA800 to PA800, PA2x to PA2X..... If you do not follow the proper protocol, you may Freeze (Memory) on your keyboard.
I hope this helps.