0.0015" is a significant amount when you work with machinists all day like I do, but as I said, it's nothing in terms of a timing chain set.
I've never seen a block blueprint so I don't know what the production tolerances are, but I can't imagine this being beyond factory tolerance!
Edit: I've also always wondered how close to true centerline the main cap surface actually is. It could be off quite a bit and still work.
