You can replace the entire backing plate by removing the four bolts in the center.
The rough spot in the center of the spindle appears to be an area that is smaller in diameter than the machined area, not the best, but as long as close to same should be OK.
It is hard to tell if the marks where the bearing set are old machine marks, or made by the bearing turning on the spindle.
It would have been great to have a photo of the bearing rollers, we trust "Made in Russia" to get our Astronauts to the International Space Station.
Our drums look fine on the outside, it would have been nice to have seen the inside.