You'll routinely be able to "find" ejector marks on semi-auto AR-type brass. Very rarely is there "nothing" there. On yours, can you feel that mark, when you run your finger over it? If no, don't sweat it. If yes, then bevel that ejector a little - it already has a nice bevel around the edge, but it's got that sharp transition...
The ejectors that leave the worst marks, no matter what, don't even have a chamfer around the edge of them, and they're square-shouldered. I learned long ago to knock those things down and save my brass, but that's only because I reload. If I didn't reload, it wouldn't even concern me.