Can anyone help me identify whether this StarWalker ballpoint is authentic?

I recently came across something unexpected.

While grabbing a pen from a drawer full of random pens, I noticed that one of them says Montblanc on it. After doing some research, it appears to be a StarWalker ballpoint.

The strange part is that I have absolutely no idea where it came from.

There are a couple of possibilities:

• My father-in-law has a habit of buying expensive things and may have forgotten about it.
• It could also have come from my grandmother's estate years ago without anyone realizing what it was.
• Someone forgot it here and we put it in the drawer?!

I'd simply like to find out whether it's genuine.

Here are a few things I've noticed:

• The "Montblanc" engraving is sharp and looks well made.
• The refill is also branded Montblanc.
• The serial number (see close-up photo) is difficult to read and looks more like it was mechanically engraved than laser engraved, which is what makes me uncertain. (I can't read it... NUL 38966L? Something like that?
• It weights 40.6g
• It has many scratches, as it lay in the drawer probably for years

I've attached a few photos, including a closeup of the weird serial number.

Are there any signs that it's authentic or fake? If needed, I can also upload more photos.

Here are the photos:

https://imgur.com/a/hgSMTt0