Another Nikon D5000 recall or just a scam?

It seems that Nikon D5000 owners that have sent their equipment to Nikon for repair and got it back (see  Nikon D5000 service advisory) started to receive letters from Nikon stating that it is “strongly recommended” to return the camera for “an additional and enhanced procedure.” Here is a copy of the letter:

There is an update on Nikon’s website from August 12th (yesterday):

“As of August 12, 2009 additional product serial numbers have been added to the list of “Affected Product Serial Numbers”. If you have previously checked your camera’s serial number prior to August 12, 2009 we recommend that you try again with the updated list.”

If you are a Nikon D5000 owner, check your serial number here.

Can someone from Nikon confirm that this is not a scam?