You cannot edit the system tables in SQL 2008 (besides, those aren't the system tables, they're views)

Try

GRANT SELECT on spt_values TO public

However, the lack of that permission will not be the problem. I just tested revoking that permission to public and with it removed, as a sysadmin, I can still see all the database properties, because a sysadmin (sa or any member of the sysadmin group) has all permissions on the server implicitly and does not need any specific granted permissions.

Does that table exist in master?

Ad-hoc distributed queries is for OPENROWSET, nothing to do with system tables.