No, not just IE - wherever the browsed pages should be changed (e.g. to include those WebRep colored icons), a plugin/extension is needed.
Sandbox is an external thing handled by the drivers, so it works anyway, but WebRep, SiteCorrect, Phishing protection... they need a plugin. I certainly have one installed in Opera.
Are you saying you don't have anything in Tools / Extensions / Manage Extensions in Opera, yet you still see WebRep icons in pages?