Not a stupid question at all! If you'll look on the back of the box down in the bottom right corner, there is a white square where the UPC code is. The Printing number is just above the UPC code.
If it says "First Edition FSD1001" above the UPC on my copy, does that mean my copy of Castle Panic is a first printing? If that is the case, I think the Product Code for the different versions database need to be updated to make them more distinct. My guess is some of the version pictures also will need updated.