It's hard to tell due to shadows but in the picture it looks like the sight isn't flat in the dovetail. They bubba'd that sight into the dovetail alright. That's the first time I've seen that happen before.
If you planning on milling, might as well refinish the slide while your at it. Maybe CZ can give you a store credit or a couple of magazines for your trouble. That would be my angle when I called them.
Cheers,
Toby