I've made my own item types. Can I use this add-on to return a 410?
Yes. Just hook into the 410_gone_data code event, and add an array to the $data array:
controllerName => array(table_name, field_name)
The controller name is the name of the controller giving the 404. The table name is the name of the table that holds the data for that controller. The field name is the name of the primary key field (that is used to get the ID from the XenForo_Input object as well as checking to see if there is a key with a higher value).