duplicated OIDs ?

I have this test DB (thank's God!) where I was fooling around.
I was playing with data from a pg_dump (tables and data with OID's).
The generated SQL script doesn't check for the existence of the DB, and
doesn't use transactions.
So it failed on creating the DB, but copied the dumped data in again,
with OIDs.
So now I have duplicated records with *duplicated OIDs* !!!
I thought that would *never* happen, even with COPY table WITH OIDS FROM
stdin;

PostgreSQL 7.0.3 on i686-pc-linux-gnu, compiled by gcc 2.96

--
Dado Feigenblatt Wild Brain, Inc.
Technical Director (415) 553-8000 x???
dado(at)wildbrain(dot)com San Francisco, CA.