Here's what I got from the online status updates on my GC (it was similar updates compared with the EAD):
On November 30, 2012, we ordered production of your new card.
On December 3, 2012, we mailed you a notice that we had registered this customer's new permanent resident status.
On December 5, 2012, we ordered production of your new card (possibly something happened but message is the same)
On December 7, 2012, we mailed the new card directly to the address we have on file.
The USPS reported that they picked up mail from USCIS containing your new card on December 7, 2012.
For EAD:
On November 19, 2012, we ordered production of your new card.
On November 23, 2012, we ordered production of your new card. (possibly something happened but message is the same)
On November 26, 2012, we mailed the new card directly to the address we have on file.
The USPS reported that they picked up mail from USCIS containing your new card on November 26, 2012.
The USPS reported that your new card was delivered on November 29, 2012
Hope this helps