Yes, but you have to edit the MySQL database directly. The "status" field in the unit table is what you need to edit. Find the deleted unit and change the status flag from 4 to 1; there could be multiple units with the same title so make sure you have the latest one. Value 1 is for published units and value 2 is for editing units. The unit will show again on the site once the database edit is done. But, all the uploaded files had been permanently deleted so you will have dead file links if there were uploaded files.