I thought the rider back design was copyright
In the United States, any design or work of writing or art made earlier than 1923 is considered to be in the public domain, and the Bicycle Rider Back design has been around since 1893. Many works since that date are also public domain, but it's more on a case-by-case basis, depending on what laws were in effect at the time the work was created. Modern works, unfortunately, will only in the rarest of circumstances enter the public domain in the same lifespan as the people who were alive when the work was created, thanks to heavy lobbying of American legislators by companies leaning far too heavily on old, creaky intellectual property for their livelihood (coughDISNEYcough). Were it not for extensions of copyright law protections, Mickey Mouse himself would be public domain. Some companies are a little less fortunate, though; to the chagrin of Sir Authur Conan Doyle's estate, the original Sherlock Holmes stories the author wrote are for the most part now in the public domain in the US, despite being protected in perpetuity under British law - but they only entered the public domain I think in the past several months.
Once a copyrighted work enters the public domain, it never leaves it. It is, however, ostensibly being protected by USPC as a trademark, which is handled differently and can be renewed in perpetuity as long as it hasn't been abandoned or diluted. USPC printed these decks for Bocopo, thus Bocopo had USPC's permission to use the Rider Back design.
One could argue the strength of trademark protections of a design this old, considering how it's been used (and abused) over the years, but as USPC is a division of Jarden, a large and deep-pocketed consumer products conglomerate, there hasn't been a legal challenge, though there's been many "extra-legal" challenges in the form of Chinese printers counterfeiting USPC designs, devoid of remorse because of the protections their government provides them. This, however, is not one of those cases.