The ip-access-control handler allows for a custom status code to be set in the predicate language via the failure-status parameter:

path-prefix(/admin) -> ip-access-control(default-allow=false, acl={'192.168.0.* allow'}, failure-status=404)

However, the access-control handler doesn't allow a custom failure-status to be set (hard coded to use "403"):

path-prefix(value="/admin/") -> access-control[default-allow=false, attribute='%{REMOTE_IP}', acl={'^127\.0\.0\.1$ allow'} ]

The ability to pass a custom failure-status should be added to the access-control handler.