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.  

Swamp Thing #171, signed by hand by Kim DeMulder and authenticated by CGC with a grade of 9.6.  With Signature Series books a certified CGC witness actually observes the signing of the comic so there is no possibility of the real autograph being switched out with another.  As of this writing, there are only two copies of this book that grade higher - at 9.8 - with this being the only 9.6.  None grade lower so there are three SS copies of this book overall.  It will be shipped with the utmost care.  There are only nine copies overall (SS and non-SS) graded... last issues of a series usually have low print runs.  And, according to GPA Analysis, no SS copy of this book has ever come to market.