Is it permissible to study from university textbooks that are suspected of being pirated, given that they bear the phrase "All rights reserved"?

Mere doubt as to whether books are copyrighted does not prevent benefiting from them, because the original principle is that the university owns them or there is permission to copy. However, if you are certain or strongly believe that they are copied without the owners' permission, then the prevailing fatwa is to uphold copyright absolutely. If the reserved rights include all forms of utilization, then studying from them is not permissible. But if the purpose of the rights is only to prevent commercial printing, then it is permissible to benefit from them for study purposes.