That's not a stupid question at all. The answer is yes, you can import .FDF's from older version of the v2 sheet (it's recommended if the .FDF is from an old 1.x version of the sheet, that you manually re-enter data, as many changes were made to the sheet with v2, not the least of which was the switch to D&D 3.5e). I've made every attempt to make importing old data as complete as possible. Some data may be lost due to changes, but when you perform the import, a dialog will inform you as to what data did not import and will need to be manually re-entered.
If you have any trouble with the import, let me know and I'll help you out.
