Deleting a generic device does not delete the files from the bootp file directory location (that is, the location where the user staged the BootP files for the specific generic device). These files must be manually deleted from the BootP file location for the specific device. Deleting a generic device through the SDM user interface only deletes the device from the SDM database.
You must decide if the device-specific bootp files for the deleted device should be retained, or if they are no longer needed.