Signed versions of this comic exist with the following Clobbering Time
Certificate of Authenticity.
The comics were in a normal comic book bag with a standard white
backing board. The bag was sealed with a gold sticker which reads
"CLOBBERING TIME LIMITED EDITION Seal of Authenticity". There may be
more than one set of limited edition comics for this issue signed by
one or more different creators. Signed comics,
labels, and Certificates of Authenticity can be forged, so they
are not listed on the checklist.
Here is an image of the sticker:
This is the Certificate of Authenticity.