That's an anachronism. We made handles be retroactively green only about a year ago, and it wouldn't have been green at the time. But it was morally green. (Edit: a la https://news.ycombinator.com/item?id=28816050)

Didn't he have a different color/tint of green for the username?

I'm not sure I understand your question but there has been only one "noob green" since I've known the code.

Sorry, it is almost certainly a Mandela effect-thing -- I (mis-)remember the username subtly standing out. I looked at old page renders on archive.org but none seems to support my claim.