I am not sure if I am looking at mint errors, excessive wear, or simple damage to these coins. Is that damage or a defect on the 1955 coin? What on earth happened to the 1940 coin? There is no rim damage on it, so I am not in the least sure what that is. In the case of the 1957D the issue is one of them has a rather broad 7 font compared to the ones I usually see on 1957D coins. I am providing both a comparison photo and a close up of the 1957D coin.
Post Mint Damage. The damage was done after it left the mint. The first one looks like it visited a parking lot for parts of its life.
I was wondering if the first one had been sand blasted long ago, just for a second, but so long ago the pitting tarnished too. I wasn't sure about the 1940 coin because of the hook at the bottom of the 9, to me that looked more like something done at the mint.