OK. Let me answer.
Yes it is permanent (REV).
Yes. It was first introduced as we know it for the 2009 Cruise collection. Very soon after it was added to the permanent line. I was like that for several years. I think around 2015/2016? (cant't remember exactly right now) it was taken out of the permanent line. Was hard find, but put out as seasonal for a while. After a while, it was put backing the permanent line (REV).
Not really. Some say they can detect minor color differences, but honestly they are completely insignificant.
To Me:
Gold - Extremely classy, con - can make the beige have more of a yellow tone. Prefer in M/L
Silver - More casual, Fresh looking, Con - unless you are a silver lover or don't like gold, GHW is the better combo. Prefer this in Jumbo.
It still can be a little harder to track down than the black.
Hope this helps!