If they don't show up on the first 20 pages of Google then I would say they're pretty obscure.
And if they're not on the first 20 pages they probably won't show up on any English language Google site at all.
Since using all the keywords possible surrounding this car don't produce any results it's possibly not solvable from a computer situated anywhere except Norway..
I think it is quite hard to define what obscure means when it comes coachbuilders here. I've searched for plenty of coachbuilders in the past that produce absolutely no results at all even if I know the name of the company and where no one seems to have any info about the company. This is not on that kind of level of obscurity.
I have a book (which have some text in both English and German in addition to Norwegian) which dedicates 7 pages to the coachbuilder with history and pictures of the cars. When I searh for the name of the company then I still find a active company with the same which seems to be successor to coachbuilder, I find pictures of a few restored buses that appears to wear their coachworks, and I find a Norwegian blog post about coachbuilding which mention them with their name. But of course I do have a Norwegian IP.
I don't think this car is featured online yet, but it should be possible to find the name of the company online at least. It is also possible to ask more question about the coachbuilder to narrow it down.