This is the original cone nut of a new coaster brake hub I bought recently. I didn't install it yet, it's new.
What bothers me are those weird stains / corrosion signs on the bearing surface. It looks like the chrome plating is damaged (or whatever plating is on them) by corrosion (caused by improper storage conditions?), or physical damage (over tightening?). Just my speculations.
Video (for different angles / light reflections):
Is it a good idea to just ride it and recheck its condition after a couple of rides? Or will it just fail right away? Can I polish it with sandpaper?