I thought that was kind of an odd choice for controls on an american made bike like that, but even that other throttle on the bike with steel wheels looks like a nicely made euro chain pull with type. I don't know anything about their snowmobiles but maybe they worked with a supplier that had stuff like that or something. Grips kinda look like Magura's but not sure. I would spend some time hunting and looking at the foreign made moped type bikes of the early 70's as I think that's were you might find that pattern and be able to find a match if you need one of those as well.
I think that Fantic may have used some of the CiTe stuff on some of the models they sold as Broncco's here as well.