Japanese cars do not have fog lamps at the rear. However fog is common in some parts of Hokkaido (northern island of Japan) so it is very common (might even be a legal requirement, not sure) to fit rear fog lamps. Hence "Hokkaido" spec.
For S15 there is a different column stalk and different rear combi lamp.
As this was in the days when Nissan was more interested in technical excellence than making money all vehicles (in Japan, not sure of Aus and NZ) had the wiring built into them and the lamp in the gauge unit.
I've got the column stalk part number written down at work but I'm on holiday at the moment. I also have a list of S15 rear lamp units, haven't yet worked out which is the Fog lamp version.