Goldmoor (mod) lore friendly?
There's nothing to contradict anything in the mod, and the content has been heavily based on lore. However, as with any mod, there's a bunch of things that had to be made up. I'd say that it's as lore friendly as possible.
is goldmoor mentioned in any TES lore?
Not by name. It's logical that the area would be a grassland, but it is never named. (That's a reeeaaally old video...)