Regarding the comics industry recent reholder scandal / scam, please note that all books I sell were submitted directly by me to CGC at various comic conventions (as well as the occasional private signing event).  I do not buy already graded books and then resell them.  So every CGC item I have for sale was graded by CGC and then came directly to me and not through another dealer.  Please further note that photos, prints, and original art sketches (that are not on actual comic books but are rather just on sketch paper or the like? i.e. anything certified by CGC that does not have a grade, are not searchable on their site by the serial number.  Only graded comics and magazines - items with grades - are searchable by serial number.  However, for such items not searchable on their site, you can call CGC Customer Service and they can verify the item authentication over the phone.  

About the item: 

This postage stamp and envelop First Day of Issue cancellation (FDI) was released by the United States Postal Service in honor DC Comics Super Heroes (and it debuted at the 2006 San Diego Comic Con. It is signed by hand by Joe Giella (who inked the image depicted on this particular stamp) and certified by CGC as part of their special Signature Series.