Re the KAC 300-meter flip sight:
Actually, now that I take it out to look at it, it has a small mark on the knurling of the windage knob. If you picture the serrations of the windage knob as being "lands and grooves", four of the lands have had the finish worn though on a perpendicular "scratch" mark. The width of the scratch is 0.031 inches wide by 0.130 inches long, as measured by my calipers.
So, it's not exactly "as new".