My steelbook has those dots as well.
I did some research and I think the US version doesn't have those. They are not visible on this guys video: https://www.youtube.com/watch?v=AGW7gasuuRM
At 1:40 - 1:47 you can see some spots as well, but not nearly as many as on mine. His backside seems flawless, but it's hard to tell.