I think the note refers to the socket itself. I recently had a replacement mobo which was second hand and before i put the cpu in i remoced the plastic socket cover and checked the socket pins. i found one bent and another broken off.
This was a board returned from the manufacturer and overclockers have kindly replaced this 2nd faulty board with a new P35 chipset version.
Basically, make sure you have the socket cover on until your ready to install the cpu and check the socket prior to cpu install.
I don't think you need to worry about the other stuff you mentioned as that sounds like coatings.
as for the stretch marks, if they are angular and uniform, i think you'll find that it's connecting tracks that go all over the motherboard.