Sun May 08, 2016 3:07 pm
No, that is no longer required.
When the pool started, the country code was sort of required because it would enable the pool
to give you servers that are "close" to you.
But later, a GEO-IP service was added to the DNS service for pool.ntp.org and now it will give you
close servers without having to specify the country code.
(of course there can be occasional mistakes due to incorrect data in the GEO-IP database)