Oups, sorry but I misunderstood your question.

Yes, for such a case like this one:

Derived& derived=...
boost::reference_wrapper<Base> reference(derived);
reference.get().function();

the call to function() will be polymorphic.

What is not possible with boost::reference_wrapper is this:

boost::reference_wrapper<Derived> derived(...)
boost::reference_wrapper<Base> base = derived

(and this what I does not understand in the conception of this class)