There are no copyright marks on the item, which can be seen at the link. At bottom is Country of origin USA and the number 27035--this probably refers to the print job of the poster.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.
{{Information |Description=Poster for the 1934 film ''The Law of the Wild''. |Source=[http://www.ebay.com/itm/Law-of-the-Wild-Stock-One-Sheet-Movie-Poster-Rex-King-of-the-Wild-Horses-1934-/201274345343?pt=LH_DefaultDomain_0&hash=item2edce2c77f eBay] [h...