Hi,
my legs are a little shorter than yours, and I ride a 170mm. A 28" inseam is sometimes a little long. It's a matter of personal preference. The threads in the frame are delicate; it might be a good idea to let a bike shop yank that out.
Measure the difference in length between your left and right legs. That you didn't notice the difference in crank arm length makes me curious. Some guys with a leg that is longer prefer different length crank arms. I think it's a cool idea; but have been too lazy to pursue it.