I shook the Google tree and it left me even more convinced that I should find a decades-long linguistics scholar encased in a library tower of a gothic mansion to untangle that etymology but it did point out that skyscraper is a modern kenning and that would not have occurred to me 
I do think you're both right though. I *think* that both the old Norse ken and the Scottish ken are the same because the Scottish one came via the North Germanic languages -- Norwegian, Icelandic, Faroese -- rather than Celtic/Gaelic which would make it a long lost ancestor. It would seem apt: Anyone I've ever met from up the top of Scotland, and especially the Hebrides, has such a different way of speaking with an accent that's so soft and with a real kind of relaxed shape to it that has far more in common with Norwegian than Scots English. Maybe that's a remnant of Scots Gaelic though? I've never met anyone that speaks that as a first language.

I do think you're both right though. I *think* that both the old Norse ken and the Scottish ken are the same because the Scottish one came via the North Germanic languages -- Norwegian, Icelandic, Faroese -- rather than Celtic/Gaelic which would make it a long lost ancestor. It would seem apt: Anyone I've ever met from up the top of Scotland, and especially the Hebrides, has such a different way of speaking with an accent that's so soft and with a real kind of relaxed shape to it that has far more in common with Norwegian than Scots English. Maybe that's a remnant of Scots Gaelic though? I've never met anyone that speaks that as a first language.