The Standard says that the answer to your question is yes:
[C++03] : 24.1.4 Bidirectional iterators
Table 75—Bidirectional iterator requirements (in addition to forward iterator)
expression return type operational assertion/note
semantics pre/post-coindition
======== ============ ============ ====================
--r X& pre: there exists s such
that r == ++s.
post: s is dereferenceable.
--(++r) == r.
--r == --s implies r
== s.
&r == &--r