Stamp/Mark between the lugs?

[Sub58]

Hello and good day,

got my first Sub ever and removed the bracelet for putting it on a nice Nato strap.

After that I found a small round mark over a lug hole (second photo).

In this forum I found a similar photo of a mark at another users Sub.



Is this normal and a mark/stamp by Rolex because it is the same location?

Or was this done by removing the spring bar? I cannot imagine that a small springbar has so much force to dent this hole. Normally I see only superficial scratches from the spring bar.

I never saw something like that on other watches. I know this will not hurt the watch but I am interested what this is.