UNIQUE constraint and indexing

Is the index, created implicitely by "UNIQUE" constraint, the same
kind as created explicitely with "CREATE INDEX"?  In other words,
is the following piece of SQL redundant?

create table foo (
       bar serial primary key,
       baz text not null unique );
create index foo_baz_idx on foo(baz);

Many thanks,
-- 
Arcady Genkin
i=1; while 1, hilb(i); i=i+1; end