Mont Blanc Meisterstruck Ball Point Issue?

[fespo276]

My wife got in the regular habit of buying me pens back in the day when I was still practicing law. I have since left that profession, but still have some of the pens. I started carrying this Mont Blanc on a regular basis again and I love it

However, I noticed a strange mark under the clip, as if we're "ground down" for some reason. I know the serial number is stamped on the outside round part of the clip, which is visible on mine (although small and hard to read).

Any thoughts from the experts? Should I doubt the authenticity if the pen?

Thanks for any help.