A dead or abandoned status for a trademark application means that specific application is no longer under prosecution within the USPTO, and would not be used as a bar against your filing. It does not necessarily mean that there are not other marks that the trademark examining attorney would cite. It is also possible to revive an abandoned application (for example, if the USPTO declared the application abandoned for failure of the applicant to respond to an Office action, but the applicant later proved that a response was sent and the USPTO simply failed to match it with the file in a timely manner, then the case could be revived). Also, regardless of the status of an application within the USPTO, the owner may still claim common law rights, i.e, the mark may still be in use in commerce.
Source: U.S. Patent and Trademark Office.