Is there something wrong with this lens and is it worth buying?

[abmich]

Hey guys. I'm new in the checking lens process. I stumbled upon this second-hand lens (Nikon 24-120) at an affordable price but I saw these weird looking defects on the mount. Can anyone help to identify what it is and whether this is worth buying?

 

[Derrel]

It looks like normal wear and tear nothing to worry about

 

[greybeard]

I'm just curious, which 24-120 is it, the 3.5-5.6 for f/4?