You don't need to switch any "enable EJBs" plugs to run EJBs within WebLogic. However, you must deploy them according to the WebLogic specific procedures described at e-docs.bea.com.
The biggest difference to the Sun specification is probably the weblogic-ejb-jar.xml descriptor, which is described at
http://e-docs.bea.com/wls/docs70/ejb/reference.html#1186416