Bi-Directional replication without changing scema on subscriber

Hello - I am a newbie to Replication.
Can I setup Bi-Directional replication without introducing the guid column
on the subscriber? All the tables have Primary Keys.
Thanks.
-A
Adam - yes - columns are only added for updatable subsriptions and merge.
Cheers,
Paul Ibison SQL Server MVP, www.replicationanswers.com
(recommended sql server 2000 replication book:
http://www.nwsu.com/0974973602p.html)