Fks 185 gold and black are the same binding except for paint job.  the fks 185 and 120 however are 2 differant bindings in general.  the 185 uses a racestock toe and heel, where as the 120 uses the production toe, (dual action 3 just like a scratch or axial) and a racestock heel.  Reason being is that for the lighter racers out there they do not need the race stock toe...
FKS 185 Black are not availible on proform, they are a limited production that the U.S. does not bring in alot of, hence why they are basicly team issue.  There still around though...