There are no copyright notices on the dust jacket.
Using the search term "Firestarter" and looking at the year 1980, we see that there are two possibly relevant copyright numbers: TXu000038308 and TX0000570285.
Both registrations only refer to the literary work and not the dust jacket.
Thus there are no copyright registrations for the dust jacket. The entire jacket is placed into the public domain.
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 (70 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.