Hi Becky,
this should give you the names. the dal_code is the object id.
select u.user_name , u.first_name||' '||u.last_name Who , cg.last_updated_date When_Customised
from cmn_grids cg, cmn_sec_users u
where dal_code='project'
and principal_type = 'USER' and principal_id = u.id and u.USER_STATUS_ID = 200