DragThing can import and export docks as XML files. To export a dock select it and choose "Export" from the File menu. To import a dock choose "Import" from the File menu and select an XML dock file.
You can also import all the docks and settings from a "DragThing Preferences" file created by an older version of DragThing. This will overwrite all the existing settings and unsaved changes to docks will be lost.