Yes, these guys are scared of what they have built and unleashed upon the world.
No, they are not. If they were they would do something substantive. Instead they are asking for regulatory capture. That is what people do when they want to prevent competition.
Their arguments are internally inconsistent because they claim that only their models are this powerful, but then they want regulations that will keep down new competitors, who by definition (according to them) are not a hazard because their models are not powerful enough.
Finally, no laws can prevent nations which don't respect the UN (like any of the members of the UNSC for starters) from developing their own models which don't respect whatever regulations these guys claim they want, so they would be worthless.