Two questions about /etc/apt/sources.list

["Zhenguang Mo \(163\)" <zhgmo@public.sta.net.cn>]

Hi,

Q1: 
is http://security.debian.org/dists/ and
http://security.debian.org/debian-security/dists/ the same thing?

Q2: do i also need to have a line saying
        deb http://security.debian.org/debian-non-US potato/non-US main
contrib non-free
    for non-us update?

thanks
Mo