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:  

World's Finest #173 from 1968, signed by hand by Jim Shooter and authenticated by CGC with a grade of 5.5.    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.  This issue features the first Silver Age appearance of Two-Face, pre-dating Batman #234 by three years (Batman dresses as Two-Face).  Of note, GPA Analysis does not record any sales of a Signature Series copy of this book (in any grade). It will be shipped with the utmost care.