Yes, clams look different from different angles, it's the way the patterning come together.
I read the provided link. I am not sure how that link was so important to post given this board's feelings about --, especially since "the evidence" was basically a guy being told that they lights can effect color, a fact that he disagrees with personally.
If the lights were such a factor, your green corals would also appear blue. Clear color difference. Perhaps, they remove the color blind person from the clam sorting duties?