Very well done, TBR! It will be interesting to see the finished project.

For the sight blade, I would suggest masking off the whole barrel except the sight and bead blasting it. For some reason, blueing is always darker and more consistent on a bead blasted surface than a polished one (cold blue anyway). This would give the sight a dark matte finish similar to having just smoked it with a carbide smoker, only much more durable.

On my stainless guns, I use green Scotchbrite to finish them with. It gives a nice brushed finish, but I think the factory finish is a little finer than that.