I\'m trying to find IBM Worklight Studio v5.0.0.3 (Eclipse plug-in).
The Eclipse Marketplace provides only the latest version (5.0.6).
It seems that IBM does not
The eclipse marketplace version is the free Developer Edition. It runs completely within eclipse and there's no standalone Worklight server.
If you've install a separate Worklight server (on Liberty, WAS, or Tomcat) then you're running the Worklight Consumer or Worklight Enterprise edition and should use the studio plugin for that edition/version. As Idan mentioned, Business Partners can get the corresponding studio plugin from PartnerWorld.