Note that the copyright page is not actually on the back side of the dust jacket as the image may suggest. The back side of the dust jacket is blank. See the links below for confirmation.
Using the search term "Cujo" and looking at the year of publication, 1981, we see that there is only one possibly relevant copyright registration, namely TX0000803583. However, that registration is only for the literary work and not the dust jacket. Thus there are no copyright registrations for the dust jacket.
The entire dust jacket, minus the photo, is placed into the public domain in the US.
Public domainPublic domainfalsefalse
This work is in the public domain because it was published in the United States between 1978 and March 1, 1989 without a copyright notice, and its copyright was not subsequently registered with the U.S. Copyright Office within 5 years.
Unless its author has been dead for several years, it is copyrighted in the countries or areas that do not apply the rule of the shorter term for US works, such as Canada (50 pma), Mainland China (50 pma, not Hong Kong or Macau), Germany (70 pma), Mexico (100 pma), Switzerland (70 pma), and other countries with individual treaties. See this page for further explanation.
Uploaded a work by Jacket design by R. Adelson Jacket illustration by Steven Stroud from [https://web.archive.org/web/20230327050139/http://www.thedarktower.org/palaver/showwiki.php?title=Stephen+King+First+Editions:Cujo+-+Trade+HC thedarktower.org] ([https://web.archive.org/web/20230703083254/http://www.thedarktower.org/gallery/data/510/Cujo_trade_face.jpg direct link]) with UploadWizard
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