Under all that "patina" the components on your Sekai look like good stuff in good shape, should clean up nicely.

Those bars - Sakae Custom, Road Champion - my '84 LeTour has the exact same ones.

I've always liked the Suntour GT RD design with the open cage that lets you take the chain out. I put a Cyclone GT on my Sekai.

Looks like steel rims tho.