If you have received your copy (or copies), you may want to take a peek at the book itself and see if you have a flaking foil problem. More can be read about it here:

http://www.tolkien.co.uk/forum.aspx?g=posts&t=502

But to sum up, HC is offering to replace the book with another copy (a higher number). This may not be limited to just that one copy, and it would be very sad to find out that you have a damaged book after HC has sold out...