Nowadays, yes. But back then, I don't think the suffixes were assigned by country quite yet, especially not the first one ever. [/size]
Actually these ISO country codes were made part of ISO 3166 in 1974 and were widely used in other applications before the internet and world wide web were developed. After the advent of the internet 3166 was divided into three parts and now part 3166-1 contains these codes. They became widely published in 1997, before that you had to know where to look.
The fact I know this and remember having to write to the ISO to get updated copies prior to 1997 makes me somewhat dated.
Seeing that first web site again is definitely a trip down memory lane.