Do DN's have to be names?

["Bennett Samowich" <brs@ben-tech.com>]

Greetings and please forgive the newbie-ness of this question.

While creating a LDAP directory to centralize some UNIX system
administration, I came across the fact that a couple of our users had the
same name.  In fact the only piece of information guaranteed to be unique
across all users was the EmployeeID which is being used as the UidNumber as
well.

Would it then make sense to use the ID number as the DN?

Example:
dn: employeeID=1234, ou=Users, o=Company, c=US
cn: John Doe
employeeID: 1234
... etc. ...

-- or would it be --
dn: cn=1234, ou=Users, o=Company, c=US
cn: John Doe
employeeID: 1234

Any assistance is greatly appreciated and again forgive me if I mis-stated
something.

- Bennett