Thanks guys. I got it for $600US delivered to my door. The lens is actually in very good condition, both the body of the lens and the numbers and letters printed on the lens, just a few light scratches there. The lens is very nice also. Using a torchlight, the white marks is below the inner lens towards the side, looks like it is off the black metal there. Maybe I will negotiate for a higher compensation than his suggested $20.
Looking back at the photo's it was showing a bit when the lens is angled to the side. When the photo is taken parallel to the camera the marks do not show up. The seller replied to my email and said he didn't noticed those marks.