Regarding the markings. Brown trout's original range was the UK, the majority of Europe, parts of Asia, and even north Africa (Morocco).
This a vast territory. They are all the same species, but their markings and coloration varied greatly in different places.
Various strains were imported into the US, and you can see quite a bit of variation in brown trout here, in both wild and hatchery browns.
If you Google "brown trout" and look at the images, you'll see a lot of variation.
By the appearance of the fins, I think it is a hatchery trout.